Fine-needle aspiration cell sampling apparatus

ABSTRACT

Apparatus and methods for performing fine-needle aspiration biopsies are disclosed. Each method and apparatus includes a needle having an opening which can be occluded during both the penetration and withdrawal stages of the aspiration cycle. After penetration of the target area, the needle is reciprocated a predetermined number of times determined by the desired cytological sample yield. The needle is unoccluded during the reciprocation phase of the cycle. Both manual and automatic apparatus for performing the fine-needle aspiration biopsy procedures in accordance with the disclosed method are disclosed. Numerous sheath configurations for various biopsy applications are illustrated, including those applicable to prostate and breast or other soft tissue biopsies and for use in conjunction with ultrasonic transducers. Alternative needle configurations are disclosed to improve sample yield, reduce coring and minimize needle fouling.

This application is a continuation of application Ser. No. 159,320,filed Feb. 23, 1988, now U.S. Pat. No. 4,989,614, 02/5/91.

BACKGROUND OF THE INVENTION

The present invention relates to methods and apparatus for takingsamples of cells from discrete tissue areas. The taking of such samplesis necessary in the cytological diagnosis of suspect tissue areas suchas tumors.

Various techniques have been used to take cells from tumors in order toestablish whether they are benign or malignant. The choice of a specifictechnique depends on several factors, including the location and size ofthe area to be sampled, the susceptibility of the area to complicationssuch as infection, and the ease of use.

One commonly used technique is the so-called core needle biopsytechnique wherein a relatively large hollow needle (e.g., 14 gauge) isforced into the tissue to be sampled and then retracted to yield a coresample suitable for histological evaluation. The taking of core needlebiopsy specimens is particularly prevalent in the diagnosis of prostaticcancer in the United States. The popularity of this technique isattributed in part to the minimal training required to perform theprocedure. In fact, it not infrequently results in complications due tothe inevitable traumatization of the tissue by the relatively largeneedle.

An alternative to the core needle biopsy technique is the so-calledfine-needle aspiration technique. Cytological diagnosis with the aid offine-needle puncture and aspiration started in the late 1950's, when itwas shown that individual cells collected from tumors by means of thistechnique could be recognized and classified. The fine needle aspirationtechnique offers numerous advantages over core needle biopsy. Forexample, with respect to the cytological diagnosis of prostatic cancer,fine needle aspiration can be performed as an outpatient procedurewithout anesthesia or bowel preparation. Further, the patient can beinformed of the diagnosis almost immediately and there is an extremelylow incidence of complications (1% in 14,000 cases). Moreover,aspiration cytology has proven to be more accurate in prostate cancerdiagnosis than conventional core needle histological biopsy. In summary,fine needle aspiration biopsy is an accurate, inexpensive and safemethod of diagnosing cancer.

Current fine-needle aspiration apparatus and techniques, however, sufferfrom several disadvantages, which have contributed to limiting theirwidespread acceptance in the United States.

U.S. Pat. No. 3,595,217 discloses a method and apparatus for fine needleaspiration biopsy of the prostate. The method and apparatus disclosed inU.S. Pat. No. 3,595,217 are very similar to the method and apparatuscommonly used throughout Europe and increasingly used in the UnitedStates. However, the disclosed method and apparatus are cumbersome touse, requiring, in practice, at least one highly trained person with anassistant to successfully perform the procedure since the needle isfirst inserted in the patient, and a syringe is thereafter attachedwhile the operator's hand remains in the patient. Moreover, thedisclosed method and apparatus do not readily lend themselves to the useof a stylet during penetration and withdrawal of the needle.Furthermore, the insertion, withdrawal and reciprocation of the needleduring the procedure are not precisely determinable since the procedureis performed manually with no means to precisely monitor needlemovement. In addition there is a lengthy learning curve that can only beovercome by performing many manual (conventional) fine-needle aspirationbiopsies under proper instruction.

U.S. Pat. No. 4,605,011 to Naslund discloses yet another prior artattempt to solve the problems associated with fine-needle aspirationmethods and apparatus. The Naslund cell sampling methods and apparatus,however, have several disadvantages. First, because a stylet is not usedto occlude the tip of the needle during the aspiration procedure, thereis a danger of patient and sample contamination. For example, inprostate aspiration, the absence of a stylet increases the risk ofcontamination of the aspirated sample and inoculation of the prostatewith enteric bacteria present in the rectal vault when the needle ispassed through the rectal mucosa into the suspected tumor in theprostrate gland. The Naslund apparatus and method further require thatthe tip of the biopsy needle be introduced into the suspected tumorwithout predictability or repeatability, because the operator is unableto precisely determine the forward excursion of the needle whenpenetrating the target area. Also, the persistence of vacuum in theneedle and adjacent connecting tube of Naslund after release of thetrigger at the conclusion of the biopsy could tend to cause (i)aspiration of contaminants or debris, such as rectal mucosa and/orbacteria residing in the rectum, and (ii) potential loss of sample intothe connecting tube. Furthermore, Naslund employs a single gauge fineneedle, thus limiting the total amount and recoverability of cellsample. Accordingly, the Naslund cell sampling apparatus is not wellsuited for certain applications, such as the cytological diagnosis ofprostatic cancer.

Accordingly, it is an object of the present invention to provide anapparatus and method for fine-needle aspiration which simplify andstandardize the fine-needle aspiration technique.

It is a further object of the present invention to provide a fine-needleaspiration apparatus and method which allow the needle to be occludedduring the penetration and withdrawal stages of the procedure to avoidintroducing contaminants into the sample or the region being biopsied.

It is a further object of the present invention to provide a fine-needleapparatus and method which enable a single person to perform the biopsyprocedure.

Another object of the present invention is to provide a device capableof performing a fine-needle aspiration biopsy quickly and safely,preferably in an out-patient setting, such as the practitioner's office.

It is a further object of the present invention to provide a fine-needleapparatus and method which will standardize and simplify the aspirationprocedure by automatically performing one or more steps of theaspiration procedure.

It is a further object of the present invention to provide a fine-needleaspiration cell sampling apparatus having a failsafe feature whichautomatically occludes the needle tip, and retracts the needle inemergency circumstances.

It is a further object of the present invention to provide a fine-needlebiopsy apparatus which is entirely disposable or in which all partssubject to contamination are disposable.

It is another object of the present invention to provide a fine-needleaspiration apparatus and method which facilitate the collection ofcytological samples without coring the tissue in the region beingsampled.

It is also an object of the present invention to provide a fine-needleaspiration apparatus and method which facilitate the collection of asufficient quantity of cells to enable an accurate cytological diagnosisto be made (i.e., malignant vs. benign).

It is a further object of the present invention to provide apparatus andmethods which simplify and facilitate the expression of cytologicalsamples retrieved through fine-needle aspiration.

These and other objects will become apparent to those skilled in the artupon reviewing the summary of the invention, and the detaileddescription and drawings of the preferred embodiments of the inventionhereinafter set forth.

SUMMARY OF THE INVENTION

The present invention relates to improvements in apparatus and methodsfor performing biopsies by fine-needle aspiration of cytologicalsamples. In accordance with the method of the present invention, theoperator performing the biopsy locates the sheath in the proximity ofthe biopsy target area. During this initial location stage, the sheathand needle are positioned with respect to each other such that theneedle tip is obscured by the end of the sheath. In accordance with themethod, the opening of the needle is occluded during this stage of thefine-needle aspiration procedure. Thereafter, the needle is movedforward with respect to the sheath, causing the occluded needle to enterthe target area. Openings in the needle are then unoccluded and vacuumis applied to the needle. The needle is thereafter reciprocated, causingthe cytological sample to be drawn into the needle. After apredetermined number of reciprocations (determined by the desired sampleyield), the needle openings are again occluded, the vacuum is releasedand the needle is then withdrawn. Because the needle openings areoccluded both during penetration and withdrawal, contaminants are notdrawn into the needle. Moreover, occlusion of the needle openings duringpenetration minimizes the introduction of contaminants from thepenetration path to the target area, thereby reducing the chance ofinfection in the target area.

Disclosed herein are several preferred fine-needle aspiration biopsyapparatus embodiments for performing the above-described method. Each ofthe preferred embodiments enable the biopsy procedures to bestandardized, include mechanisms for occluding the needle duringpenetration and withdrawal, and renders feasible the performance of thebiopsy by a single operator.

A first preferred embodiment of the invention is a fine-needle biopsyapparatus which automatically performs the above-discussed fine-needleaspiration method. In particular, the first embodiment comprises a gunhaving a syringe and needle. The needle protrudes from the gun and issurrounded by a sheath, which is removably secured to the gun. Inoperation, the sheath and needle are positioned next to the target area,and the operator initiates the automatic aspiration procedure bysequentially activating safety and trigger mechanisms. After activation,the first preferred embodiment of the present invention automaticallyinitiates the method steps, including (1) penetration of the needle intothe target area while the opening of the needle is occluded; (2)unoccluding the needle opening and applying vacuum to the needle; (3)reciprocating the unoccluded needle to collect the cytological sample;(4) again occluding the needle opening and releasing the vacuum; and (5)withdrawing the needle. After the cycle has been automatically completedand the cytological sample has been obtained, the sample is expressedonto a microscope slide by of one of several disclosed methods.

The gun of the first preferred embodiment utilizes a disposableassembly, comprised of a syringe, syringe plunger, variable diameterneedle, stylet and sheath. The stylet is connected to the plunger, andis dimensioned such that it occludes the needle opening when the plungeris in its forwardmost position, but unoccludes the needle opening whenthe plunger is withdrawn. The disposable assembly is removed afteroperation, and the non-disposable portion of the apparatus (i.e., thegun) is ready for use without sterilization.

The first preferred embodiment is electromechanically operated viasolenoids and a D.C. motor. However, D.C. stepping motors or servomotors can be utilized in lieu of one or more of the electromechanicalsolenoids and D.C. motor to actuate the apparatus. In a modification ofthe first embodiment, pneumatic cylinders and pistons can be used inlieu of the electromechanical devices for actuating the apparatus.

Numerous safety features are incorporated in the first preferredembodiment of the present invention, including a mechanism for ensuringretraction of the needle into the sheath upon release of the trigger bythe operator. An alarm and safety breaker are provided to respectivelyinform the operator and disable the apparatus should a mechanical orelectromechanical problem occur. Furthermore, the automatic apparatuswill not operate if there is insufficient power to complete the entireaspiration cycle.

In further modifications of the first preferred embodiment, the syringeand plunger are not disposable, but instead are incorporated within thereusable portion of the apparatus. Only the needle, stylet and sheathare disposable. In this embodiment, the plunger incorporates a grabbermechanism, which is either mechanically or electrically actuated, tograb the stylet for movement with the plunger to, respectively, occludeand unocclude the needle openings.

In a second preferred embodiment of the present invention, the needle,stylet, sheath, and syringe arrangement of the first embodiment of theinvention are manually operated in lieu of the automatic apparatus ofthe first preferred embodiment of the invention. As with the automaticapparatus, the stylet of the manual apparatus occludes the needleopening during the insertion and withdrawl stages of the procedure. Agage and stop are provided to enable the operator to monitor themovement of the needle during the procedure, facilitatingstandardization of the procedure. As with the automatic embodiment, theprocedure can be performed by a single operator without the need forextensive training or experience. The entire apparatus can be disposableor, alternatively, the syringe, plunger, needle, stylet and sheath canbe disposable and used with a reusable handle apparatus.

As will be appreciated from the foregoing discussion, the first andsecond embodiments of the present invention utilize a variable diameterneedle and a stylet to selectively occlude the needle opening. Third andfourth preferred embodiments of the invention are also disclosed, inwhich the stylet is omitted, and the needle is instead occluded duringinsertion and withdrawal by an outer sleeve, which is retracted duringthe aspiration procedure to expose the needle openings and allowcytological sample to be drawn into the needle. The third embodiment ismanually operated, and the fourth embodiment is automatic.

In each of the above-discussed embodiments, several alternative sheathdesigns can be implemented depending upon the type of biopsy to beperformed. For trans-rectal biopsies of the prostate, a sheath having afinger guide and handle portion is used to facilitate manipulation bythe operator. For biopsies of soft, fleshy tissue regions (e.g., thebreast) a disc-like sheath end can be implemented to stabilize andlocate the sheath and needle on the fleshy tissue. The sheath can alsobe designed to accommodate an ultrasonic transducer so that the targetarea can be ultrasonically probed to position the sheath and needle.Additionally, several alternative needle designs can be implemented toreduce coring by the needle and minimize needle fouling.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawingswherein like reference numerals refer to similar parts throughout theseveral views and in which:

FIGS. 1a-1f are schematic cross-sectional views illustrating the methodof the present invention;

FIG. 2 is a cross-sectional view of a needle and sheath assembly of thepresent invention;

FIG. 3 is a cross-sectional view of the needle and sheath assembly ofFIG. 2 taken along line III--III

FIG. 4 is a cross-sectional view of the needle and sheath assembly ofFIG. 2 taken along line IV--IV;

FIG. 5 is a cross-sectional view of the needle and sheath assembly ofFIG. 2 taken along line V--V;

FIG. 6 is a cross-sectional view of the needle and sheath assembly ofFIG. 2 taken along line VI--VI;

FIG. 7 is partial side cross-sectional view of the needle and sheathassembly of FIG. 2;

FIG. 8 is an enlarged cross-sectional view of the sheath and needle tipof the needle and sheath assembly of FIG. 2;

FIGS. 9a-9c are cross-sectional views of alternative needle and styletarrangements;

FIGS. 10a and 10b are cross-sectional views of an alternative needle andsheath arrangement of the present invention;

FIG. 11 is a cross-sectional view of a further alternative needle andsheath arrangement of the present invention;

FIG. 12 is a cross-sectional view of a modification of the needle andsheath assembly of the present invention;

FIG. 13 is a cross-sectional elevation of a first preferred embodimentof fine-needle aspiration apparatus of the present invention;

FIG. 14 is a cross-sectional view of the fine-needle aspirationapparatus of FIG. 13 taken along line XIV--XIV;

FIG. 15 is a cross-sectional view of the fine-needle apparatus of FIG.13 taken along line XV--XV;

FIG. 16 is a top cross-sectional view of the fine-needle apparatus ofFIG. 13;

FIG. 17 is a schematic diagram illustrating the control sequence of thefirst embodiment of the present invention;

FIG. 18 is a control circuit for the first embodiment of the presentinvention;

FIGS. 19a and 19b are cross-sectional views illustrating modificationsof the first embodiment of the present invention;

FIGS. 20a and 20b are cross-sectional views illustrating still furthermodifications of the first embodiment of the present invention;

FIG. 21 is a cross-sectional view of a resevoir test apparatus for usewith the first embodiment of the present invention;

FIG. 22 is a cross-sectional view of a manual second embodiment of thepresent invention;

FIG. 23 is a cross-sectional view of a modification of the manual secondembodiment of the present invention;

FIGS. 24a-24c are cross-sectional views of a manual third embodiment ofthe present invention; and

FIG. 25 is a cross-sectional view of an automatic fourth embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1a-1f schematically illustrate the positions of a needle 2, stylet3, syringe 4 and plunger 5 relative to a fixed casing 1 and sheath 6during a fine needle aspiration procedure using the first preferredembodiment of the apparatus of the present invention. More specifically,the schematic representation illustrates the movements of a firstmovable unit comprised of needle 2, syringe 4 and the means forlongitudinally moving the same, and a second movable unit comprised ofstylet 3, plunger 5 and means for longitudinally moving the same. Thefirst and second movable units are adapted for movement relative to oneanother or together as a carriage assembly. Many of the movements of theneedle, stylet, syringe and plunger illustrated in FIGS. 1a-1f arecommon to several embodiments of the invention, as discussed in moredetail herein with reference to specific embodiments of the invention.

In FIG. 1a, the carriage (including the first and second movable units)is in its initial position "A". To commence aspiration of suspecttissue, the operator manually aligns the tips of the sheath, needle andstylet at or near the region to be sampled, hereinafter referred to asthe target area. The operator then initiates the automatic aspirationprocedure by, for example, manually triggering a switch located adjacenta pistol grip of the apparatus.

In accordance with a first preferred embodiment of the presentinvention, upon initiation of the automatic aspiration procedure, thecarriage (and hence the needle 2 and stylet 3) moves forward a firstpredetermined distance to the position "B" shown in FIG. 1b. Thismovement advances the tips of the needle and stylet past the end of thesheath into the target area. This step is particularly desirable forthose instances where it is not practical to manually position the tipsof the needle and stylet at the target position (e.g., when the targetarea is in a remote region, such as the prostate gland). Automation ofthis step facilitates standardization of the aspiration procedure andhelps ensure that the operator does not overshoot or undershoot thetarget area. When the present invention is used in an environment wherethe tips of the needle and stylet can be accurately, conveniently andsafely manually positioned into the target area, this step can beomitted.

FIG. 1c illustrates the next step in the operation of the firstembodiment, wherein after the initial forward movement of the carriage(position "B"), the carriage moves backwards a second predetermineddistance to a position "C" located between positions "A" and "B". Thisstep, which is omitted in manual embodiments of the invention, is inaccord with a fail-safe aspect of the present invention, discussed inmore detail below, whereby when power is cut off from the device, allcarriage components are brought to a fully retracted position.

FIG. 1d illustrates the next step of the aspiration procedure in whichthe second movable unit, which includes the plunger 5 and the stylet 3,is retracted relative to the first movable unit, which includes thesyringe 4 and the needle 2, to an extended carriage position. Inaccordance with the present invention, and as discussed in more detailherein, this step serves at least two important functions. First,retraction of the stylet provides a passage between the tip of theneedle and a larger diameter cell sample storage portion of the needlelocated rearwardly of the tip of the needle. Second, retraction of theplunger simultaneously reduces the pressure in the cell sample storageportion of the needle. Because the retraction of the second movable unitrelative to the first movable unit both opens a passage between the tipof the needle and the cell sample storage portion of the needle andcreates a partial vacuum in the cell sample storage portion of theneedle, a suction force is created at the tip of the needle causingsample material to be drawn into the cell sample storage portion of theneedle.

Although cell sample is immediately drawn into the cell sample storageportion as the plunger is withdrawn, reciprocation of the needle withinthe target area is required to increase the sample yield. Thus, inaccordance with the present invention, the carriage (while in theextended position) is reciprocated between the positions illustrated inFIGS. 1d and 1e, i.e., between positions "B" and "C".

After sufficient sample has been collected, the reciprocation cycleterminates. The second movable unit (including the stylet 3 and plunger5) is then returned to a forward position as indicated in FIG. 1f so asto occlude the passage between the needle tip and the cell samplestorage portion of the needle. Additionally, the return of the styletand plunger to the forward position seals and removes the vacuum fromthe cell sample storage portion of the needle.

After the second movable unit is fully returned to the position shown inFIG. 1f, the carriage is returned to the position shown in FIG. 1a thuscompleting the aspiration procedure. The operator then withdraws theapparatus from the patient, removes the sheath, opens a cover of theapparatus, removes the syringe and needle from the apparatus,disconnects the syringe and stylet from the needle, connects a secondsyringe (filled with air) to the needle, and expresses the collectedcell sample from the needle onto a slide. At this time, the cytologicalanalysis of the cell sample can be performed. Additionally, since theapparatus is restored to its original state as shown in FIG. 1a and allcomponents that were in contact with the patient (i.e., needle 2, stylet3, sheath 6) are discarded, the apparatus is ready to receive a newsterile sheath, needle and syringe assembly for the next fine needleaspiration procedure. Sterilization of the reusable portion of theapparatus is not required.

An important feature of the present invention is the unique constructionof the needle and stylet which allows the aspiration procedure to becompleted automatically. Moreover, the configuration of the needle andstylet obviates the need for removal of the stylet before commencing theprocedure and allows the sample storage portion of the needle to befully sealed during both the penetration and withdrawal stages of theprocedure. Finally, the configuration of the needle and styletfacilitates removal of a cytological sample without coring the targetarea.

A preferred needle construction is described hereinafter with referenceto FIGS. 2-8. FIG. 2 is a partial cross-sectional view of a needle 2, astylet 3 and a needle sheath 6. As shown in FIGS. 2-8, the stylet 3 hasa uniform circular cross-section along its length. The needle tube,however, has a variable cross-section. In particular, the needleincludes a narrow diameter portion 16 (e.g., 22 gauge) and an expandeddiameter portion 17 (e.g., 18 gauge). Both portions of the needle 2 arehollow thus permitting the stylet 3 to extend therethrough.

The exterior diameter of the stylet is substantially the same as theinterior diameter of the narrow portion 16 of the needle so that whenthe stylet extends fully through the narrow diameter portion 16 of theneedle, the stylet occludes the tip 19 of the needle and substantiallyoccupies the entire interior space of the narrow portion of the needleto thereby seal the needle. Further, when in the fully extendedposition, the tip of the stylet 26 and the tip of the needle 19 aresubstantially continuous so as to provide a substantially continuouslytapering leading edge for effectively penetrating and separating tissuewithout coring when the needle and stylet protrude beyond the sheath asillustrated in FIG. 8.

The interior surface of the expanded portion 17 of the needle has alarger diameter than stylet 3. Thus, even with the stylet extended intothe expanded portion of the needle, a space is provided between theexterior diameter of the stylet and the interior diameter of theexpanded portion of the needle. This space defines a chamber or volume,which is referred to herein as the cell sample storage portion 20 of theneedle. Cellular material drawn into the needle is collected in the cellsample storage portion for storage until the needle is removed from thetarget area and the sample is thereafter expressed in the mannerdescribed above.

The needle sheath 6 shown in FIGS. 2-8 functions to safely guide theneedle to the target area, and prevents patient or operator injury.Significantly, and as discussed in more detail below, when the device isin its initial position, the tip of the needle does not extend beyondthe sheath. This prevents inadvertent puncture and resulting infectionof the operator or patient which might result from puncture by aprotruding needle, and enables safe guidance of the sheath to theproximity of the target area.

As illustrated in FIGS. 2, 5 and 7, in some applications (e.g., whenperforming a trans-rectal prostate biopsy), a finger guide 13 isprovided at or near the end of the needle sheath 6 to assist theoperator in manipulating the tip of the sheath. Additionally, tofacilitate manipulation of the needle assembly, a sheath positioninghandle 14 is provided. Handle 14 is attachable (e.g., by snap fit) tothe sheath 6 at any desired location along a handle attachment area 12so as to be positionable for either right or left hand usage andlongitudinally adjustable.

FIGS. 9a-9c illustrate modified needle embodiments which may beimplemented to increase the yield of sample collected during the fineneedle aspiration procedure and/or to minimize coring which occursduring the procedure. In particular, radially extending ports or holes 7are provided proximate the tip for cell collection during the aspirationprocedure. In the embodiments of FIGS. 9a and 9b the ports are providedin addition to the opening at needle tip 19. In the embodiment of FIG.9c, the opening at needle tip 19 is omitted, and only side ports areutilized for sample collection. As illustrated in FIG. 9a, a series ofholes 7 can be provided at longitudinally spaced locations.Additionally, in a further embodiment (not shown) holes or ports can beradially spaced about the circumference of the needle to facilitatesample collection. If several ports are spaced in the radial directionabout the circumference, it will be appreciated that such ports shouldbe located only on one circumferential segment of the needle of lessthan or equal to 180° to facilitate subsequent expression of the sampleonto a microscope slide. As illustrated in FIGS. 9b and 9c, the portscan have a gradual chamfer 8 to reduce coring of the tissue beingsampled and to minimize fouling of the holes or ports with tissue anddebris. Additionally, the closed tip design of FIG. 9c facilitatestissue separation and reduces coring during reciprocation of the needle.

A modified sheath is illustrated in FIGS. 10a and 10b. Although thesheath and finger guide illustrated in FIGS. 2-8 are suitable for use incertain applications, including trans-rectal prostate biopsies, it isnot ideally suited for biopsy applications in fleshy tissue or where thetarget area is proximate to the surface of the skin. The embodimentilustrated in FIGS. 10a and 10b is identical to the embodiment of FIGS.2-8, except that finger guide 13 is omitted and sheath 6 defines adisc-shaped sheath tip 25 at its distal end. The disc-shaped sheath tipis adapted to be pressed firmly against the skin in the proximity of thetarget area, and functions to stabilize the sheath while the biopsy isbeing performed. As will be appreciated by those ordinarily skilled inthe art, numerous sheath configurations could be implemented to adaptthe present invention to biopsies in various regions of the body.

A further modification of the sheath is illustrated in FIG. 11, whichrenders the apparatus suitable for use with a conventional ultrasonicprobe. Sheath 6 is secured within a probe retainer 21, which is shapedto conform to and accommodate a conventional ultrasonic probe (notshown). In prostate biopsy applications, for example, the probe withinits retainer is inserted trans-rectally in lieu of the operator's fingerto locate the target area. Upon location of the target area, the sheathis positioned such that the target area will be penetrated by the needleupon actuation of the apparatus. The aspiration procedure is thenperformed in the manner herein described.

FIG. 12 illustrates a further modification of the needle and styletassembly. As illustrated in FIG. 12, a filter 22 is mounted within thewider diameter portion 17 of needle 2 at a connection end 18 thereof.Filter 22 is annular in shape, and defines a center region through whichstylet 3 is tightly inserted. Filter 22 ensures that the samplewithdrawn from the target area remains within the cell sample storageportion 20 of the needle, and is not drawn into the syringe bodyupstream of the filter. The filter further functions to wipe the styletas the stylet moves within the needle. By wiping the stylet andcapturing the sample within the cell sample storage portion 20 of theneedle, subsequent expression of the sample onto the microscope slide isfacilitated and the amount of sample which remains unexpressed from theneedle is reduced. Furthermore, the filter functions to wipe the styletclean when the plunger and stylet are removed for expression purposes,thereby reducing the dangers of operator infection.

FIGS. 13-16 illustrate, in detail, the structure of a first preferredembodiment of the fine-needle aspiration cell sampling apparatus of thepresent invention. The apparatus includes a casing 1, needle 2, sheath6, stylet 3 syringe 4 and plunger 5, as discussed above. The needle canbe of any of the constructions and include one or more of the featuresdescribed above. The sheath can also be of any of the configurationsdescribed above and should be selected in view of the particularapplication for which the apparatus is being used. The needle isconnected to syringe 4 via conventional luer-lock connections 18, 31.Similar connections 11, 81 join sheath 6 to casing 1. The syringe 4 maybe of conventional construction or of a construction especially suitedfor use in conjunction with the first embodiment of the fine needleaspiration cell sampling apparatus. Stylet 3 is fixed to plunger 5 andis removable therefrom via stylet grip 27. The plunger and the syringetogether define a variable volume air chamber 34 through which thestylet extends. As is well known in the art, the plunger 5 is providedwith a plunger head 33 which includes at least one sealing portion tomaintain an airtight fit between the perimeter of the plunger head 33and the interior of the syringe 4.

As illustrated in FIGS. 14-16, a pair of syringe carriage guide rods 60are supported by and fixed with respect to the casing 1 at syringe guiderod supports 62 so as to extend parallel to the needle 2 and syringe 4.A pair of U-shaped syringe support brackets 41 and U-shaped plungerbracket 45 are slidably supported on the guide rods 60. As shown in FIG.13, the syringe support brackets 41 are connected to one another by asyringe carriage 40. The rear U-shaped syringe support bracket 41includes locking groove 47 for receiving a syringe body flange 35.Plunger support bracket 45 similarly has locking groove 39 for receivingplunger body flange 36. Thus, U-shaped brackets 41 support the syringe 4(and the needle 2 connected thereto) for movement in the longitudinaldirection of the guide rods 60. Similarly, plunger head 33 and U-shapedplunger support bracket 45 support the plunger for movement in thelongitudinal direction of the guide rods 60. A pair of helical springs61 are provided coaxially with portions of the guide rods 60,respectively. The springs 61 extend between a front end of the casing 1and a side portion of forward U-shaped support bracket 41 and functionto bias the U-shaped bracket in a rearward direction.

As shown in FIGS. 13-15, front and rear syringe retainers 42 arepivotally secured to the front and rear U-shaped syringe supportbrackets 41 by hinges 44. Latches 43 lock the syringe retainers 42 tothe U-shaped brackets 41 to secure the syringe within the U-shapedbrackets. Latches 43 are unlatched by syringe retainer release buttons48 (FIGS. 14 and 15). A similar hinge latch and release button (notshown) are employed to secure a plunger retainer 46 to the U-shapedplunger support bracket 45.

Additionally, as shown in FIGS. 14 and 15, a top portion or cover 82 ofcasing 1 is pivotable with respect to the remainder of the casing abouta hinge 79. A latch assembly, comprised of latch 89 and release button83, is provided to enable selective locking of the cover portion 82 ofthe casing to the remainder of the casing. Cover 82 is spring biased tothe open position by a conventional spring (not shown). In use, latchassembly 83, 89 is released and the pivotable cover portion 82 of thedevice is swung open when it is necessary to replace the disposablesyringe assembly, comprised of the needle 2, stylet 3, syringe 4 andplunger 5. A cover switch 122 (FIG. 14) is provided to sense closure ofthe cover and to prevent operation of the apparatus when the cover ortop portion 82 is open, as described in more detail below.Alternatively, or in addition, a sheath switch 121 is provided at thesheath connection to prevent operation of the apparatus when the sheathhas not been connected in the manner described below.

A pair of signal LED's 131, 134 are provided on a top portion of thecasing. More specifically, a red LED 134 is provided to indicate that anaspiration procedure is in progress and a green LED 131 is provided toindicate that the device is ready for operation. Flashing of either ofthe LED's indicates an operational fault as discussed in detail below.

The apparatus further includes a main solenoid 70 which, when energized,drives a syringe carriage drive bar 57 against the operative bias ofsprings 61. The syringe carriage drive bar is secured to an assembly,including a plunger motor 55, plunger motor gear box 56, lead screwsupport bar 58 and lead screw support bar end plate 59. The motor 55 andreduction gear box 56 are conventional and need not be discussed furtherherein.

The output of gearbox 56 rotatably drives a plunger lead screw 50 whichin turn linearly drives plunger support bracket 45 via a threaded nutportion 49 of support bracket 45. The rearward end of lead screw 50 isrotatably journaled in end plate 59 in suitable bearings or bearingsurfaces.

As is apparent from the foregoing, the syringe 4, needle 2, syringesupport brackets 41, syringe carriage 40, motor 55, gearbox 56, drivebar 57, lead screw 50, lead screw support bar 58 and end plate 59 aremovable longitudinally together as a first movable unit. Additionally,stylet 3, plunger 5 and plunger support bracket 45 are movablelongitudinally together as a second movable unit. Moreover, when thelead screw 50 is not rotated, the first movable unit and second movableunit are fixed with respect to one another and movable longitudinallytogether as a carriage assembly. The first movable unit, second movableunit, and carriage assembly are all constrained to move longitudinallyonly along guide rods 60.

A spring loaded detent 65 is provided to prevent retraction of the drivebar 57 and the remainder of the carriage assembly beyond a predeterminedpoint corresponding to the position "C" in FIG. 1. Detent 65 is springbiased into a retracted position to allow retraction of the carriageassembly beyond point "C" when the power is off, as described in detailbelow. A detent solenoid 66 is provided to force detent 65 upwardsagainst the bias of spring 67, when actuated, thereby preventing theretraction of the carriage assembly beyond point "C".

The rearward retraction limit defined by detent 65 (i.e., correspondingto position "C" in FIG. 1) is adjustable via detent positioning screw 68threaded to casing 1. The positioning screw is adjustable at detentpositioning dial 71 such that the precise point of position "C" issettable by the operator with a screwdriver or special tool adapted toaccommodate the detent dial face. The forward excursion of the carriageassembly (corresponding to position "B" in FIG. 1) is limited byadjustable drive bar stop screw 69. Stop screw 69 is threaded to thecasing 1 and is adjustable via drive bar stop dial 72 to vary thelocation of position "B". The total operational excursion of thecarriage assembly is thus adjustable via detent positioning dial 71 anddrive bar stop dial 72.

A lower portion of casing 1 defines a pistol grip 84 having a chamber 90for storing a battery 92 (not shown in FIG. 13). Battery 92 is removableand is accessed via a cover 91. A particularly suitable power source isa conventional rechargeable Ni-Cad battery. Of course, otherconventional power sources can be used. A battery low voltage sensor 113(not shown in FIG. 13) is provided within chamber 90. Trigger 86 pivotson trigger pivot 87 and is located within trigger guard 85. The triggeris operatively connected to operational control switch 117, mainsolenoid cut-off switch 118 and detent solenoid cut-off switch 119,discussed in more detail below. Located forward of trigger 86 on safetyguard 88 is safety switch 115. Safety switch 115 and trigger 86 may beoperated by either the right or left hand. As described in detail belowin connection with the control circuitry, the safety switch 115 must beactivated before activating the trigger switch 86 to enable the device.

Several other switches and sensors are included to control and monitorthe operation of the apparatus. Power switch 110 is provided to energizethe electrical and electromechanical components of the apparatus. Apower switch breaker 111 deenergizes the apparatus upon completion of anoperational cycle. Front drive bar sensor 125 and rear drive bar sensor126 are respectively fixed to the adjustable drive bar stop screw 69 andthe detent assembly 65, 66 and respectively sense the forwardmost andrearwardmost excursion of the carriage. A plunger front limit sensor 127is fixed to syringe support bracket 41 and senses when plunger supportbracket 45 is in its forwardmost position. Plunger rear limit sensor 128is fixed to lead screw support bar end plate 59 and senses when theplunger support bracket 45 is in its rearwardmost position. Originsensor 120 is fixed to the rear of casing 1 and senses when the carriageassembly has returned to the origin position (i.e., corresponding toposition "A" in FIG. 1). Switches or sensors 125, 126, 127, 128 and 120may be conventional microswitches, Hall-effect switches or any otherwell known or suitable switches sensors, including, but not limited to,inductive, optical, fluidic, mechanical or electromechanical switches orsensors.

Furthermore, although the carriage and the detent 65 are described ascontrolled by main solenoid 70 and detent solenoid 66, either or bothsolenoids could be substituted with other appropriate means, including,but not limited to, D.C. servo or stepping motors with appropriatelinkages providing the desired reciprocatory movements.

Having thus described the structure of the first preferred embodiment ofthe present invention, the following is a discussion of the mechanicaloperation of the first embodiment of the fine-needle aspirationapparatus and method of the present invention. For purposes of thisdiscussion, it is assumed that cytological biopsy of a suspicious areaof the prostate gland is to be performed.

Before a biopsy is initiated, the suspected tumor area must be examinedand assessed as to its dimensions and distance from the proposedentrance point of the needle tip 19. In operation, the needle excursionis determined by the positions of the detent positioning screw 68 andthe drive bar stop screw 69. To accommodate dimensional variations inthe size and location of target areas, changes of the screw settings canbe made manually by using the dial adjustment tool to turn themulti-turned-numerically-indicated dials 71 and 72. First the distanceof the suspected tumor area from the entrance point of the needle tip 19is set on the detent positioning screw 68 via dial 71. Thereafter, thedesired total distance the needle tip 19 should traverse during thereciprocation mode is set on the drive bar forward stop screw 69 viadial 72. Dial 72 should thus be adjusted to a setting equalling theinitial depth of the target area (i.e., the setting of dial 71) plus thediameter of the target area in millimeters. For example, if the depth ofthe forward boundary of the target area is assessed to be 5 mm and itsdiameter 15 mm, then dial 71 is set at 5 mm and dial 72 at 20 mm.

The operator thereafter ensures that a charged battery 92 is installedin the apparatus by closing the casing cover 82 and turning on the powerswitch 110 to check the charge level of the battery. Green LED 131 willflash if insufficient charge remains to safely complete the cycle, asdescribed in more detail below in connection with the control circuit.

The operator thereafter selects an appropriate sterile dispensablesyringe and sheath assembly for the procedure being performed. Casingcover 82 is thereafter opened by depressing the cover release button 83until the casing cover pops open. Syringe retainers 42 and the plungerretainer 46 are similarly opened by depressing their respective releasebuttons until they pop open. The operator then grasps the disposablesyringe and sheath assembly, slides the sheath 6 away from the syringeabout an inch and places the syringe body 4 in the syringe supportbrackets 41 and the plunger body flange 36 in the plunger supportbracket 45. Syringe retainers 42 and plunger retainer 46 are thensnapped closed and the casing cover 82 is closed and locked by pushingdown on the top of the casing cover until it snaps shut. Sheath 6 isthen slid along the needle toward the apparatus and sheath luer-lock hub11 is locked onto the casing luer-lock connection 81.

Sheath positioning handle 14 is then snapped onto the sheath handleattachment area 12 at a position appropriate for the operator's handsize and in the direction of right or left-hand operation, asappropriate.

The operator then positions the tip of the sheath and needletrans-rectally proximate to the target area, palpating with his or herfinger tip to precisely locate the target area. Automatic aspiration isthereafter initiated by closing the safety switch 115 and depressingtrigger 86.

Upon depressing the trigger, the first solenoid 70 is energized therebycausing the drive bar 57 to move forward against the bias of springs 61until it abuts drive bar stop screw 69, actuating front drive bar sensor125. Forward movement of the drive bar 57 causes the entire carriageassembly, including motor 55, gearbox 56, lead screw 50, end plate 59,syringe support brackets 41, syringe carriage 40, plunger 5, plungersupport bracket 45, syringe 4, stylet 3, and needle 2, to move forwardto a position corresponding to the "B" position in FIG. 1. The controlcircuit further energizes detent solenoid 66. The upper surface ofdetent 65 is cammed so that rear syringe support bracket 41 can easilymove past the detent in the forward direction, but cannot move rearwardover the detent. The forward excursion of the carriage assembly causesthe needle tip 19 (and stylet tip 26) to emerge from the sheath andpenetrate the target area until it reaches the far end of the targetarea, in this example 20 mm. The control circuit (described below)thereafter deenergizes main solenoid 70 so that the carriage assemblyretracts under the bias of springs 61. Because detent 65 is driven toits uppermost position by the detent solenoid 66, complete retraction ofthe carriage is prevented. The carriage thus retracts to the "C"position in FIG. 1, in this instance 5 mm, so that the tips of theneedle and stylet are now at the near end of the target area. Rear drivebar sensor 126 is actuated when the carriage reaches the semi-retractedor "C" position.

When the carriage is in the semi-retracted or "C" position, the motor 55is activated by the control circuit so as to rotatably drive lead screw50 through the gear box 56 to retract the second movable unit (definedby plunger support bracket 45, plunger 5 and stylet 3), with respect tothe first movable unit (defined by syringe support brackets 41, syringecarriage 40, syringe 4 and needle 2). Retraction of the second movableunit deactivates plunger front limit sensor 127.

Retraction of the plunger 5 causes the stylet 3 to retract with respectto the needle 2. Consequently, a passage is formed from the tip of theneedle 19 to the sample storage portion 20 of the needle. Additionally,the retraction of the plunger head 33 with respect to the syringe 4results in a partial vacuum in chamber 34 creating suction at the tip ofthe needle. When the plunger is fully withdrawn, plunger rear limitsensor 128 is activated, thereby causing the control circuit to turn offmotor 55.

The control circuit thereafter causes the carriage to reciprocate sothat sample is collected. Reciprocation is achieved by alternatelyenergizing and deenergizing the main solenoid 70 so that the carriageassembly is alternately moved forward by the solenoid and rearwardly bysprings 61. After a predetermined (programmable) number ofreciprocations has been sensed by the control circuit, the controlcircuit ends the reciprocation cycle and activates the motor 55 inreverse so that plunger 5 and stylet 3 are returned to their originalposition. As the stylet is returned to its original position, thepassage between the tip of the needle and the sample storage portion ofthe needle is once again sealed to prevent contamination of thecollected sample upon needle withdrawal.

When plunger 5 is completely returned to its original position, plungercarriage front limit sensor 127 is once again actuated, turning offmotor 55. Detent solenoid 66 is also deenergized, such that detent 65withdraws, permitting the carriage to return to the fully retracted or"A" position (FIG. 1) under the bias force of springs 61, thuscompleting the aspiration procedure.

Upon completion of the procedure, the sheath is withdrawn from therectum, the sheath guide is removed from the index finger and the gloveon that hand is removed and discarded. The sheath luer-lock hub 11 isremoved from the casing luer-lock 81, and the cover of the device isopened by pushing the cover release button 83. The syringe and plungerretainers 42, 46 are similarly opened and the syringe assembly isremoved from the device. The needle luer-lock hub 18 is then disengagedfrom the syringe luer-lock 31, and the syringe with the stylet 3 areseparated from the needle and discarded. A second syringe filled withair is then attached to the needle luer-lock hub 18. The sheath is thenwithdrawn and discarded and the cell sample in the needle is expressedonto a glass microscope slide for cytological examination.

FIG. 17 diagramatically illustrates the control sequence of the mainsolenoid 70, the detent solenoid 66, the motor 55, the red LED 134, andthe green LED 131 during normal operation. More specifically, FIG. 17shows a preferred control sequence wherein electrical current (shown asa solid black line) is provided to the various components which arelisted on the vertical axis at selected times during a normal cycleillustrated along the horizontal time axis.

As shown in FIG. 17, when the apparatus is ready for operation (afterthe power switch 110 is turned on), a steady green LED 131 lights.Pulling the trigger 86 (point "a" in FIG. 17) begins the cycle, causingred LED 134 to light and green LED 131 to go off. The trigger alsoactuates main solenoid 70 and detent solenoid 66. Thereafter, the mainsolenoid 70 is turned off, and the motor 55 is actuated in a clockwisedirection by motor control 153 (discussed below) at point "b". At point"c", the motor 55 is turned off and the first solenoid 70 receives apre-programmed number of current pulses. At point "d", the motor 55 isturned on in a counterclockwise direction via motor control 154(discussed below) to return the plunger to the full forward position.Finally, at point "e", the detent solenoid 66 is turned off, the red LED134 is turned off, and the rotation of the motor 55 in thecounterclockwise direction is stopped, thus ending the cycle.

From the above description, it should be apparent that operation of theaforementioned components in the above sequence results in theperformance of the fine needle aspiration procedure. In particular,activation of the main solenoid 70 causes the carriage assembly to moveforward to the "B" position (FIG. 1) while the red LED 134 indicates tothe operator that the cycle is in progress.

When the main solenoid 70 is turned off and the detent solenoid 66 ison, the carriage assembly returns to the semi-retracted "C" position(FIG. 1) under the bias of the springs 61 until detent 65 is engaged.Simultaneously, the motor turns counterclockwise to retract the plungerand stylet thereby opening a passage between the tip of the needle andthe cell sample storage portion of the needle and creating suction todraw sample material past the tip of the needle into the cell samplestorage portion of the needle.

When the plunger and stylet are fully retracted the motor is turned offand the main solenoid is pulsed to reciprocate the needle between "B"and "C" positions (corresponding to FIGS. 1d and 1e) a predeterminednumber of times.

After completion of the predetermined number of reciprocations, themotor is turned counterclockwise to return the plunger and stylet to theclosed position. After the plunger and stylet are returned to the closedposition, the detent solenoid 66 is turned off so that the carriage isreturned to the initial or "A" position (FIG. 1) by the springs. Red LED134 is then turned off, informing the operator that the operation iscomplete.

Having thus described the mechanical operation of the first embodimentof the invention, set forth below is a description of the structure andoperation of a solid-state logic circuit for controlling the firstembodiment of the invention.

As shown in FIG. 18, electronic control circuit 109 of the firstpreferred embodiment of the fine needle aspiration device is provided tocontrol the orderly operation of the various electrical indicators andelectromechanical devices of the invention. Battery 92 is provided as apower source. Manual push-on push-off type power switch 110 is providedfor connecting power from battery 92 to the electronic logic elements ofcontrol circuit 109. Power-on-reset (POR) circuit 112 is provided thatemits a momentary signal of level high (H) when power switch 110 isclosed. Three ganged switches 117-119, each a single-pole single-throwspring-loaded normally-open debounced switch, are provided to initiatethe biopsy operation when they are closed and to safely terminate theoperation in progress when they are opened. Operation control switch 117emits a signal of level low (L) when closed and a signal of level H whenopened. Main solenoid cut-off switch 118 connects main solenoid controlcircuit 160 and main solenoid 70 when closed and disconnects them whenopened. Detent solenoid cut-off switch 119 connects detent solenoidcontrol circuit 161 and detent solenoid 66 when closed and disconnectsthem when opened.

Battery voltage level sensor 113 indicates the amount of power remainingin battery 92 by emitting a signal of level H when the voltage onbattery 92 is sufficient to operate the device reliably, and a signal oflevel L otherwise. NAND gate 165 is provided for emitting an invertedlogical product between the "not" of battery voltage level sensor 113output and the output from operation control switch 117. Green flashingcontrol circuit 132, which is an astable gated oscillator circuit, isprovided that outputs a continuously oscillating signal between level Hand level L in response to an input signal of level L, and outputs asignal of level H in response to an input signal of level H. The outputof NAND gate 165 is connected to the input of green flashing controlcircuit 132.

Safety switch 115 is a single-pole single-throw spring-loaded momentarynormally-open push-button type debounced switch which emits a signal oflevel L when closed and a signal of level H when open. Single-polesingle-throw debounced sheath switch 121 emits a signal of level L whenclosed and a signal of level H when open. Cover switch 122, which is asingle-pole single-throw debounced switch, emits a signal of level Lwhen closed and a signal of level H when open. Debounced front plungerlimit sensor 127 emits a signal of level L when activated by plungersupport bracket 45 being in its forwardmost position as shown in FIG.13, and emits a signal of level H when the plunger support bracket 45 isin any other position. NOR gate 167 is provided that emits an invertedlogical sum between the output of the sheath switch 121 and the coverswitch 122. Four input AND gate 169 is provided that emits a logicalproduct between the output of operation control switch 117, the outputof battery voltage level sensor 113, the "not" of the output of frontplunger limit sensor 127 and the output of NOR gate 167. OR gate 168 isprovided that emits a logical sum between the "not" of the output of NORgate 167 and the output of POR circuit 112. Flip-flop 170 is a clockedD-type flip-flop and emits a signal at the Q output, the state of whichis dependent on the signal from the output of AND gate 169 connected tothe Data input line D, the "not" of the output from safety switch 115connected to the Clock input line C, the output of OR gate 168 connectedto the Reset input line R, and the Set input S which is held at a signallevel of L. XOR gate 133 is provided that emits a logical "exclusive-or"between the output of flip-flop 170 and green flashing control circuit132. Green LED 131 can be in one of three states: off, steady on orflashing on and off.

Red flashing control circuit 135, an astable gated oscillator circuit,is provided that outputs a continuously oscillating signal between levelH and level L in response to an input signal of level L, and outputs asignal of level H in response to an input signal of level H. The outputof NOR gate 167 is connected to the input of flashing control circuit135. Origin sensor 120 is provided which emits a signal of level L whenit is closed and it is closed if and only if the lead screw support barend plate 59 is in close proximity to it. AND gate 174 is provided foremitting the logical product between the output of flip-flop 170 and the"not" from the output of operation control switch 117. AND gate 175 isprovided for emitting the logical product between the output of originsensor 120 and the output of AND gate 174. XOR gate 136 is provided foremitting a logial "exclusive-or" between the output of AND gate 175 andflashing control circuit 135. Red LED 134 can be in one of three states:off, steady-on or flashing on and off.

Front drive bar sensor 125, which is a debounced switch, emits a signalof level L when it is closed and it is closed if and only if in closeproximity with syringe carriage drive bar 57. Debounced rear syringecarriage sensor 126 emits a signal of level L when it is closed and itis closed if and only if the bottom end of syringe carriage 40 is inclose proximity to it. Debounced rear plunger limit sensor 128 emits asignal of level L when it is closed and it is closed if and only ifplunger support bracket 45 is in close proximity to it.

Adjustable counter circuit 180 is provided to count for a programmablenumber of times input signal changes from level H to level L and foremitting a signal of level L or H. The preferable range of theprogrammable number is between one and one hundred, and can beprogrammed by micro-switches (not shown). Any count below the programmednumber causes adjustable counter circuit 180 to emit a signal of levelL. Any count at or above the programmed number causes adjustable countercircuit 180 to emit a signal of level H. The output of front drive barsensor 125 is connected to the input of adjustable counter circuit 180.The output of POR circuit 112 is connected to the Reset input C ofadjustable counter circuit 180. A signal of level H at the Reset inputwill cause adjustable counter 180 to reset the count to zero and to emita signal of level L.

Three input NAND gate 183 is provided for emitting the logical productbetween the "not" of the output of operational control switch 117, theoutput of flip-flop 170 and the "not" of the output of adjustablecounter circuit 180. Three input AND gate 184 is provided for emittingthe logical product between the output of front plunger limit sensor127, the "not" of the output of cover switch 121 and the output of NANDgate 183. OR gate 185 is provided for emitting the logical sum betweenthe output of OR gate 220 on line 238 and the output of AND gate 184.Motor counter-clockwise control circuit 154 is provided that outputs theproper voltage and current levels for turning motor 55 in acounter-clockwise direction. The output signal of OR gate 185 is inputto the motor counterclockwise control circuit 154 which is activated byan input signal of level H and turned off by an input signal of level L.

AND gate 186 is provided for emitting the logical product between the"not" of the output of operation control switch 117 and the "not" of theoutput of front drive bar sensor 125. Latch 187 is provided for emittinga constant signal of level H in response to a momentary signal of levelH at the Set input. The output from AND gate 186 is connected to the Setinput of latch 187. The output of POR circuit 112 is connected to theReset input of latch 187. A momentary signal of level H at the Resetinput R of latch 187 resets the output signal to level L. Four input ANDgate 188 is provided for emitting the logical product between the "not"of the output of OR gate 220 on line 238, the output of latch 187, theoutput of rear plunger limit sensor 128 and the "not" of the output ofadjustable counter circuit 180. Motor clockwise control circuit 153 isprovided that outputs the proper voltage and current levels for turningthe motor 55 in a clockwise direction. The output signal of AND gate 188is input to motor clockwise control circuit 153 which is activated by aninput signal of level H and turned off by an input signal of level L.

AND gate 190 is provided for emitting the .logical product between theoutput of flip-flop 170 and the "not" of the output of operation controlswitch 117. Monostable 193 is provided for emitting a momentary signalpulse of level H in response to the signal level change from L to H ofthe output of AND gate 190. AND gate 191 is provided for emitting alogical product between the "not" of the output of rear drive bar sensor126 and the "not" of the output of rear plunger carriage limit sensor128. OR gate 192 is provided for emitting the logical sum between theoutput of AND gate 191 and the "not" of the output of front drive sensor125.

Flip-flop 195 is a clocked J-K type flip-flop and is provided foremitting a signal at the Q output dependent on the state of the signaloutput by AND gate 192 connected to the Clock input line, the signaloutput by monostable 193 connected to the Set input line, the signaloutput by POR circuit 112 connected to the Reset input line, and the Jand K input lines held at a signal level H. With the J and K input linesheld at signal level H, a signal level change from L to H at the Clockinput will cause the Q output to toggle. A signal level of L at the Setor the Reset input has no effect on the Q output. A signal level of H atthe Set input immediately forces the Q output to a signal of level H. Asignal of level H at the Reset input immediately forces the Q output toa signal of level L.

Delay circuit 200 is provided for delaying the output of adjustablecounter 180. The time period of delay circuit 200 is set equal to (orgreater than) the time it takes for the motor 55 to runcounter-clockwise sufficient to fully return the plunger 5 to the closedor forwardmost position. In other words, the time period of delaycircuit 200 is equal to or greater than the time measured betweenplunger rear limit sensor 128 opening, and plunger front limit sensor127 closing, during normal operation. AND gate 196 is provided foremitting the logical product between the output of AND gate 190 and the"not" of the output of delay circuit 200. AND gate 197 is provided foremitting the logical product between the output of AND gate 196 and the"not" of the output of OR gate 220 on line 238. Detent solenoid controlcircuit 161 is provided for emitting the proper current and voltagelevel to control detent solenoid 66 in response to the signal at theoutput of AND gate 197. A signal of level H input to detent solenoidcontrol circuit 161 turns detent solenoid 66 on and a signal of level Lturns it off.

The output of delay circuit 200 is also applied, through line 245, as aninput to OR gate 226.

AND gate 198 is provided for emitting the logical product between theoutput of flip-flop 195 and the "not" of the output of adjustablecounter circuit 180. AND gate 199 is provided for emitting the logicalproduct between the output of AND gate 198 and the "not" of the outputof OR gate 220 on line 238. Main solenoid control circuit 160 isprovided for emitting the proper current and voltage level to controlmain solenoid 70 in response to the output of AND gate 199. A signal oflevel H input to main solenoid control circuit 160 turns main solenoid70 on and a signal of level L turns it off.

AND gate 201 is provided for emitting the logical product between theoutput of operation control switch 117 on line 233 and the output offlip-flop 170 on line 234. AND gate 202 is provided for emitting thelogical product between the output of AND gate 201 and the "not" of theoutput of origin switch 120 on line 235. Delay circuit 203 is providedfor emitting the same signal level as the output of AND circuit 202after a time delay. Delay circuit 204 is provided for emitting the samesignal level as the output of adjustable counter 180 via line 241 aftera time delay. AND gate 205 is provided for emitting the logical productbetween the output of origin sensor 120 on line 235 and the output ofdelay circuit 204. AND gate 206 is provided for emitting the logicalproduct between the "not" of the output of adjustable counter 180 online 241 and the output of AND gate 201. Delay circuit 207 is providedfor emitting the same signal level as the output of AND gate 206 after atime delay. AND gate 208 is provided for emitting the logical productbetween the output of origin sensor 120 on line 235 and the output ofdelay circuit 207. Delay circuit 211 is provided for emitting the samesignal level as the output of flip-flop 195 on line 243 after a timedelay. AND gate 212 is provided for emitting the logical product of the"not" of the output of origin sensor 120 on line 235 and the output ofdelay circuit 211. Delay circuit 213 is provided for emitting the samesignal level as the output of flip-flop 195 on line 243, after a timedelay. AND gate 214 is provided for emitting the logical product of theoutput of front drive bar sensor 125 on line 240 and the output of delaycircuit 213. Delay circuit 215 is provided which emits the same signallevel as the output of AND circuit 184 on line 237, after a time delay.AND gate 216 is provided for emitting the logical product of the outputof front limit sensor 127 on line 236 and the output of delay circuit215. Delay circuit 217 is provided which emits the same signal level asthe output of AND gate 188 on line 239 after a time delay. AND gate 218is provided for emitting the logical product of the output of the rearlimit sensor 128 on line 244 and delay circuit 217.

Four input OR gate 219 is provided for emitting the logical sum betweenthe outputs of AND gates 212, 214, 216 and 218. Two input OR gate 220 isprovided for emitting, on line 238, the logical sum between the outputsof OR gate 219 and AND gate 206. Delay circuit 221 is provided foremitting the same signal level as the output of OR gate 219, after atime delay. AND gate 222 is provided for emitting the logical product ofthe output of delay circuit 221 and origin sensor 120 on line 235. Threeinput OR gate 223 is provided for emitting the logical sum between theoutputs of the AND gates 205, 208 and 222. OR gate 224 is provided foremitting the logical sum of the outputs of OR gates 219 and 223. Delaycircuit 225 is provided for emitting, on line 231, the same signal levelas the output of OR gate 224 after a time delay. Three input OR gate 226is provided for emitting on line 232 the logical sum of the outputs ofdelay circuits 200 on line 245, 203 and 225.

Breaker 111 is provided for opening power switch 110 disconnecting powerto electronic control circuit 109 in response to a signal of level Hfrom the output of OR gate 226 on line 232. Breaker 111 is mechanicallylinked to power switch 110 so that closing power switch 110 also closesbreaker 111.

Fault indicating breaker 228 is provided for disconnecting the power toelectronic control circuit 109 in response to a signal of level H fromthe output of delay circuit 225 on line 231.

Buzzer control circuit 138 is provided for emitting the proper currentand voltage for sounding buzzer 137 in response to a signal of level Houtput by OR gate 223.

Having thus described the structure of the control circuit of the firstembodiment of the invention, the operation of the control circuit willnow be described with reference to the figures.

The fine-needle aspiration apparatus is controlled electronically by thestate of the manual switches and the position detecting sensors. For theapparatus to function properly the operator must open or close theswitches in a predetermined order following an instruction procedure.The apparatus is designed not to permit operation if certain safetyconditions are not met. Once in operation, the apparatus is designed tosafely terminate operation should either the operator decide to abortthe operation or if an electromechanical fault or jam occurs. Thedescription of the electronic control of the apparatus is divided belowinto six function areas: Initialization, Safety Conditions Checked,Operation, Normal End of Operation, Terminating an Operation byReleasing the Trigger, and Failsafe Shutdown of Operation Due to anElectromechanical Fault.

(i) Initialization

When power switch 110 is closed, battery 92 is connected to electroniccontrol circuit 109 providing power to the electronic logic elements inelectronic control circuit 109. The closing of power switch 110immediately triggers POR circuit 112 which sends a momentary signal oflevel H to the following: the Clear input C of adjustable counter 180which sets the count to zero and causes the output to be a signal oflevel L; the Reset input R of latch 187 causing the output to be asignal of level L, the Reset input R of flip-flop 195 causing the Qoutput to be a signal of level L, and, by way of OR gate 168, the Resetinput R of flip-flop 170 causing the Q output to be a signal of level L.

All switches and sensors are debounced. Excluding switches 110, 228, 118and 119, all switches and sensors, when closed, connect the respectivesignal lines to ground level L. When these switches are open, therespective signal lines, which are connected through current limitingresistors (not shown) to B+, are pulled to level H. In other words, anopen switch or sensor emits a signal of level H; a closed switch orsensor emits a signal of level L.

The normal initial states of all switches, sensors, indicators, andelectromechanical devices after power switch 110 is closed are set forthin Table I below:

TABLE I

110: power switch closed

118: main solenoid cutoff switch open

119: detent solenoid cutoff switch open

117: operation control switch open, emits signal of level H

113: battery voltage level sensor emits a signal of level H

115: safety switch open, emits a signal of level H

121: sheath switch closed, emits a signal of level L

122: cover switch closed, emits a signal of level L

120: origin sensor closed, emits a signal of level L

125: front drive bar sensor open, emits a signal of level H

126: rear drive bar sensor open, emits a signal of level H

127: front plunger limit sensor closed, emits a signal of level L

128: rear plunger limit sensor open, emits a signal of level H

131: green LED off

134: red LED off

55: plunger motor off

66: detent solenoid off

70: main solenoid off

137: buzzer off

228: fault indicating breaker closed

(ii) Safety Conditions Checked

After power switch 110 is closed but before operation control switch 117is closed, if battery voltage level sensor 113 is emitting a signal oflevel L indicating low battery voltage, NAND gate 165 will emit a signalof level L to green flashing control circuit 132 so that it goes intoits flashing mode emitting a signal oscillating between level L andlevel H. The signal passes through XOR gate thereby flashing green LED131 so the operator can be alerted that the battery voltage is low. Ifbattery voltage level sensor 113 begins emitting a signal of level Lafter operation control switch 117 is closed so that it is emitting asignal of level L, then NAND gate 165 will emit a signal of level Hwhich causes green flashing control circuit 132 to emit a signal oflevel H which functions to prevent green LED 131 from flashing so thatthe operator will not be distracted during an operation. Battery voltagelevel sensor 113 is adjusted so that when it detects that the batteryvoltage is low there will still be enough voltage to reliably completethe current operation.

The signal level output by XOR gate 133 is input to green LED 131 anddetermines which of the three states green LED 131 is in: a signal oflevel H turns green LED 131 off which indicates the apparatus is notready and cannot be operated until certain safety conditions are met, asignal of level L turns green LED 131 steady on which indicates theapparatus is ready and will go into operation when operation controlswitch 117 is closed, or a signal that oscillates between level L and Hcausing green LED 131 to flash on and off which alerts the operator thatthe voltage level in battery 92 is low and that battery 92 needs to becharged or replaced.

Before the device can be made to operate, the following safetyconditions must be satisfied: trigger 86 must not be squeezed, that is,the operation control switch 117 is open, battery 92 must be charged sothat battery voltage level sensor 113 emits a signal of level H, frontplunger carriage limit sensor 127 must be closed, safety switch 115 mustbe open, sheath switch 121 must be closed and cover switch 122 must beclosed. Only when these conditions are all met will flip-flop 170 emit asignal of level H causing green LED 131 to turn steady on when thesafety switch 115 is momentarily closed. After the power-oninitialization, but before the operation begins, if any safetyconditions are not satisfied, then flip-flop 170 will only emit a signalof level L when safety switch 115 is momentarily closed.

When safety switch 115 is activated the switch momentarily changes fromopen to closed which causes the output signal level to change from H toL. This signal is inverted and applied to the Clock input C of flip-flop170 causing the same signal level of the output of AND gate 169 at theData input D of flip-flop 170 to be emitted at the Q output of flip-flop170.

In this regard, by checking the signal levels input to AND gate 169, thesafety condition of the device is determined and indicated by the outputof AND gate 169: an output signal level of L indicates the device is notready; an output signal level of H indicates the device is ready.

A signal of level L output by operation control switch 117 prevents thedevice from going into operation immediately if safety switch 115 isclosed after closure of operation control switch 117. For example, ifthe operator is squeezing trigger 86 when safety switch 115 isactivated, the operation will not start.

A signal of level L output by battery voltage level sensor 113 indicatesthat the voltage of battery 92 is too low, and hence the apparatus isdisabled.

A signal of level H output by front plunger limit sensor 127 indicatesthat plunger carriage 45 is not in its initial position, either becausecarriage 45 did not return to its initial position after a previousoperation of the apparatus or because an electromechanical failureoccurred requiring that the apparatus not be operated.

A signal of level L output by safety switch 115 indicates that safetyswitch 115 is being held closed. Because flip-flop 170 will only outputthe signal level at the Data input D on a Clock input signal change fromlevel L to level H, it is necessary to release (open) the safety switch115 before pushing it closed. In other words, this safety conditionprevents the apparatus from being operative accidentally due to safetyswitch 115 being disabled, stuck closed, taped closed or manually heldclosed. Furthermore, if any of the safety conditions are not satisfiedand safety switch 115 is pushed closed, after the problem is detectedand corrected, safety switch 115 still must be released and pushedagain.

Locking sheath luer-lock hub 11 properly to casing luer-lock connection81 closes sheath switch 121. Closing hinged casing cover 82 so that itsnaps into the locked position closes cover switch 122. A signal oflevel H output by sheath switch 121 or cover switch 122, or both, islogically summed by NOR gate 167, the level L output of whichsubsequently prevents the apparatus from being ready. This preventsunsafe operation of the apparatus with sheath luer-lock hub 11improperly attached to casing luer-lock connection 81 or with hingedcasing cover 82 open or even partly open.

Further, if all the safety conditions are met and safety switch 115 isclosed momentarily and green LED 131 comes on indicating that theapparatus is ready, and if then the operator were to open sheathluer-lock hub 11 or hinged casing cover 82, which would open sheathswitch 121 or open cover switch 122, then OR gate 168 would send asignal of level H to the Reset input of flip-flop 170 which wouldimmediately output a signal of level L making the apparatus not readyand turning off green LED 131. To make the apparatus ready again in thiscase it is necessary to start over; i.e., lock sheath luer-lock hub 11properly to casing luer-lock 81 to close sheath switch 121, and closehinged casing cover 82 into the snapped locked position to close coverswitch 122, and meet all the other safety conditions before againclosing safety switch 115 momentarily.

Further, whenever power switch 110 is closed and either sheath switch121 or cover switch 122 is open, the output of NOR gate 167 will be asignal of level L causing red flashing control circuit 135 to go intoits flashing mode emitting a signal oscillating between level L andlevel H which passes through XOR gate 136 thereby flashing red LED 134so that the operator can be alerted that sheath hub 11 or hinged casingcover 82 is not properly secured or shut. The signal level output by XORgate 136 is input to red LED 134 and determines which of the threestates it is in: a signal of level H turns red LED 134 off whichindicates the operation has not begun or has been completed or has beenterminated, a signal of level L turns red LED 134 steady on whichindicates that the operation has begun and is in progress, or a signalthat oscillates between level L and H causing red LED 134 to flash onand off which indicates that either cover switch 122 or sheath switch121 has not been closed.

(iii) Operation

After all of the safety conditions are satisfied, with the output offlip-flop 170 emitting a signal of level H and green LED 131 on steady,the apparatus is ready for operation. When the operator has oriented andpositioned the tip of sheath 9 correctly as described above, theoperation is commenced by squeezing trigger 86 which closes detentsolenoid cutoff switch 119, main solenoid cutoff switch 118 andoperation control switch 117. At this point the operation of theapparatus is automatic for so long as the operator continues squeezingtrigger 86, thus keeping the operation control switch 117 closed. Thesequence of events is as follows with reference to FIGS. 1a-1f and13-18.

AND gates 174 and 190 then emit signals of level H. Monostable 193 emitsa momentary signal of level H which triggers the Set input of flip-flop195 which outputs a signal of level H. This causes the output of ANDgate 198 to be a signal of level H which makes the output of AND gate199 a signal of level H. This turns main solenoid control circuit 160 onand energizes main solenoid 70 which, in turn, draws syringe carriagedrive bar 57 forward and with it the entire carriage assembly,including: syringe carriage 40, syringe support brackets 41, plungersupport bracket 45, motor 55, gear box 56, lead screw support bar 58,lead screw support bar end plate 59, syringe retainers 42, plungerretainers 46, syringe body 4, plunger 5, stylet 3 and needle 2. Also,movement of drive bar 57 pushes needle tip 19 forward out of the tip ofsheath 9 to its full present forward excusion as shown in FIG. 1b.

As syringe carriage drive bar 57 moves forward it compresses syringecarriage helical return springs 61, and opens origin sensor 120 whichcauses AND gate 175 to emit a signal of level H which causes XOR gate136 to emit a signal of level L which turns red LED 134 on steadyalerting the operator that the operation has begun and is in progress.As syringe carriage drive bar 57 moves forward, the rear syringe supportbracket 41 passes over and forward of detent 65 and passes over andforward of rear drive bar sensor 126 closing it momentarily and thenopening it. This signal level change causes no change in the output ofAND gate 191 because plunger rear limit sensor 128 is open at this time.

Also, when AND gate 190 emits a signal of level H, AND gate 196 emits asignal of level H which, in turn, makes detent solenoid control circuit161 turn on thereby energizing detent solenoid 66 which draws detent 65upwards.

As syringe carriage drive bar 57 continues to move forward it makescontact with drive bar forward stop screw 69 stopping its forward motionin the full forward excursion position as shown in FIG. 1b. Also, inthis position syringe carriage drive bar 57 is detected by front drivebar sensor 125 causing front driver bar sensor 125 to close emitting asignal of level L. This causes the output of OR gate 192 to go from asignal of level L to H which causes flip-flop 195 to change states,producing a signal of level L. This causes AND gate 198 to output asignal of level L which causes AND gate 199 to output a signal of levelL which, in turn, causes main solenoid control circuit 160 to turn offmain solenoid 70.

Also, at the time when front drive bar sensor 125 closes, it emits asignal level change from H to L which causes adjustable counter 180 toincrement its internal counter from zero to one. However, until counter180 reaches the programmed number, it continues to emit a signal oflevel L.

Also, at the time when sensor 125 emits a signal of level L, AND gate186 emits a signal of level H which causes latch 187 to change from L toH which in turn causes AND gate 188 to emit a signal of level H. Thiscauses the motor clockwise control circuit 153 to turn on and to turnmotor 55 in a clockwise direction which, by means of gear box 56, turnsplunger lead screw 50 in a clockwise direction thereby moving plungersupport bracket 45 rearward. This begins retracting plunger 5 and stylet3, respectively, from syringe body 4 and needle 2. Retraction of plunger5 creates low pressure within syringe body 4. When stylet 3 clears thenarrow diameter portion 16 of needle 2, sample is drawn into needle tip19.

Picking up from the point in time when main solenoid 70 is turned off,syringe carriage helical return springs 61, which have been compressed,now release their stored energy and push syringe carriage 40 rearwardalong with the entire carriage assembly. Consequently, needle 2 ispartly withdrawn back into sheath 6. As syringe carriage drive bar 57moves rearward, front drive bar sensor 125 opens which causes OR gate192 to emit a signal of level L. Syringe carriage drive bar 57 continuesto be pushed rearward by return springs 61 until the lower end of rearsyringe support bracket 41 is stopped by detent 65. In this intermediateposition, rear drive bar sensor 126 detects syringe carriage lower end41 and closes, emitting a signal of level L.

The rearward movement of plunger support bracket 45 causes plunger frontlimit sensor 127 to open thereby emitting a signal of H. When plungersupport bracket 45 reaches the proximity of lead screw support bar endplate 59, plunger rear limit sensor 128 detects the position of plungersupport bracket 45 and closes emitting a signal L. This causes AND gate188 to emit a signal of level L which causes motor clockwise controlcircuit 153 to turn off motor 55 which stops the rearward motion ofplunger support bracket 45 as shown in FIG. 1d. When plunger rear limitsensor 128 closes it also causes AND gate 191 to emit a signal of levelH.

Next begins a reciprocation cycle. The signal of level H at the outputof AND gate 191 causes OR gate 192 to change from signal level L to Hwhich causes the Clock input C of flip-flop 195 to toggle the Q outputto a signal of level H. This causes AND gate 198 to emit a signal oflevel H which causes AND gate 199 to emit a signal of level H whichturns main solenoid control circuit 160 on and energizes main solenoid70. This draws syringe carriage drive bar 57 forward and with it theentire carriage assembly, and pushes needle tip 19 forward. As syringecarriage drive bar 57 moves forward it compresses syringe carriagehelical return springs 61, and it opens rear drive bar sensor 126 whichcauses AND gate 191 to emit a signal of level L. This causes OR gate 192to emit a signal of level L.

As syringe carriage drive bar 57 continues to move forward it makescontact with drive bar forward stop screw 69 stopping its forward motionin the full forward excursion position as shown in FIG. 1e. Also, inthis position syringe carriage drive bar 57 is detected by front drivebar sensor 125 causing front drive bar sensor 125 to close emitting asignal of level L. This causes OR gate 192 to emit a signal of level Hwhich causes flip-flop 195 to toggle and to produce a signal of level L.This causes AND gate 198 to output a signal of level L which causes ANDgate 199 to output a signal of level L which, in turn, causes mainsolenoid control circuit 160 to turn off main solenoid 70.

Also, at the time when front drive bar sensor 125 closes, it emits asignal level change from H to L which causes adjustable counter 180 toincrement from one to two. However, because it has not reached theprogrammed number, adjustable counter 180 continues to emit a signal oflevel L.

When main solenoid 70 is turned off, syringe carriage helical returnsprings 61 which have been compressed now release their stored energyand push syringe carriage 40 rearward along with the entire carriageassembly. Needle tip 19 is again partly withdrawn back into the tip ofsheath 9. As syringe carriage drive bar 57 moves rearward, front drivebar sensor 125 opens which causes AND gate 192 to emit a signal of levelL. Syringe carriage drive bar 57 continues to be pushed rearward byreturn springs 61 until the lower end of rear syringe support bracket 41is stopped by detent 65. In this position, rear drive bar sensor 126detects rear syringe support bracket 41 and closes emitting a signal oflevel L which causes AND gate 191 to emit a signal of level H.

At this point the adjustable counter 180 is at count two and theapparatus is about to repeat the series of events included in thereciprocation cycle. Each time the apparatus completes a cycle the countof adjustable counter 180 is incremented. When the count equals theprogrammed number, adjustable counter 180 emits a signal of level H andthe normal end of operation procedures and functions begin.

(iv) Normal End of Operation

When adjustable counter 180 emits a signal of level H this causes NANDgate 183 to emit a signal of level H which causes AND gate 184 to emit asignal of level H. This causes OR gate 185 to emit a signal of level Hwhich, in turn, causes motor counter-clockwise control circuit 154 toturn plunger carriage motor 55 counter-clockwise which, by means of gearbox 56, turns plunger lead screw 50 in a counterclockwise directionwhich moves plunger support bracket 45 forward pushing plunger 5 forwardinto the syringe body 4, and pushing stylet 3 forward into needle 2occluding the needle. Plunger 5 must return back into syringe body 4 sothat the low pressure will be relieved and needle 2 will be occluded bystylet 3 to prevent contamination of the sample upon withdrawal of theneedle from the target area.

As plunger carriage motor 55 continues to turn counterclockwise pushingplunger support bracket 45 forward, plunger rear limit sensor 128 opensand then plunger front limit sensor 127 closes which causes AND gate 184to emit a signal of level L. This causes OR gate 185 to emit a signal oflevel L which causes motor counter-clockwise control circuit 154 to turnoff plunger carriage motor 55. This stops the motion of plunger carriagelead screw 50 and the forward motion of plunger support bracket 45 andplunger 5.

Simultaneously, when adjustable counter 180 emits a signal of level H,AND gate 198 is caused to emit a signal of level L which causes AND gate199 to emit a signal of level L. This causes main solenoid controlcircuit 160 to turn off main solenoid 70 which allows syringe carriagehelical return springs 61 to push syringe carriage 40 rearward openingfront drive bar sensor 125, and then closing rear drive bar sensor 126and stopping rearward motion when the lower end of syringe 41 supportbracket contacts detent 65.

Simultaneously, when adjustable counter 180 emits a signal of level H,delay circuit 200 is caused to begin its delay period for a length oftime equal to or greater than the time it takes for plunger carriagemotor 55 to push plunger support bracket 45 forward until plunger frontlimit sensor 127 emits a signal of level L. At the end of the delayperiod, delay 200 emits a signal of level H which causes AND gate 196 toemit a signal of level L which, in turn, causes AND gate 197 to emit asignal of level L. This causes detent solenoid control circuit 161 toturn off detent solenoid 66 which allows detent spring 67 to draw detent65 downward. This allows syringe carriage helical return springs 61 topush syringe carriage 40 rearward to the original starting positionillustrated in FIG. 1a. This causes origin sensor 120 to close therebyemitting a signal of level L which causes AND gate 175 to emit a signalof level L which in turn causes XOR gate 136 to emit a signal of level Hwhich turns off red LED 134.

Also when delay circuit 200 emits a signal of level H, OR gate 226 emitsa signal of level H which, in turn, activates breaker 111 therebydisconnecting battery 92 from control circuit 109.

(v) Terminating an Operation by Releasing the Trigger

Should the operator release trigger 86 thereby opening operation controlswitch 117, before adjustable counter 180 reaches the programmablenumber, a failsafe termination of the operation will occur in thefollowing sequence.

Opening operation switch 117 causes the signal in line 233 to assume asignal of level H. Since the Q output of flip-flop 170 is also at asignal of level H during an operation, AND gate 201 is satisfied andproduces a signal of level H. Since adjustable counter 180 has not yetreached the programmable number, adjustable counter 180 produces asignal of level L on line 241 which is inverted and applied to AND gate206 along with the output of AND gate 201, causing the output of ANDgate 206 to produce a signal of level H. This satisfies OR gate 220which produces on line 238 a signal of level H, which is applied to ORgate 185 which, in turn, activates motor counter-clockwise controlcircuit 154 to turn plunger carriage motor 55 counter-clockwise which,by means of plunger carriage motor gear box 56, turns plunger lead screw50 in a counter-clockwise direction which moves plunger support bracket45 forward pushing plunger 5 forward into the syringe body 4, andpushing stylet 3 forward to occlude needle 2.

A signal of level H on line 238 also blocks control signals from beingapplied to motor clockwise control circuit 153 with AND gate 188, andblocks control signals from being applied to solenoid control circuits160 and 161 with AND gates 199 and 197.

Simultaneous with the opening of operation control switch 117, maincontrol cut off switch 118 and detent solenoid cut off switch 119 alsoopen, thereby deenergizing main solenoid 70 and detent solenoid 66. Thedeenergization of main solenoid 70 and detent solenoid 66 allows syringecarriage 40 to move rearward through action of syringe carriage helicalreturn springs 61, along with the entire carriage assembly, to theorigin position shown in FIG. 1a.

If there are no operational erros, origin sensor 120 will close, therebyproducing a signal of level L on line 235 when syringe carriage 40returns to the original starting position as shown in FIG. 1a. Thesignal of level L produced by origin sensor 120 is inverted and appliedto AND gate 202 along with the signal of level H produced by AND gate201. This causes AND gate 202 to produce a signal of level H which isdelayed by delay circuit 203 and applied to OR gate 226. This causes theoutput of OR gate 226 to produce a signal of level H on line 232 which,in turn, causes breaker 111 to open power switch 110, thereby removingpower from control circuit 109.

If, however, an error does occur and syringe carriage 40 does not returnto the original starting position (for example, if an electromechanicalfailure or jam has occurred), origin sensor 120 will not open beforedelay circuit 207, which delays the output of AND gate 206 and producesa signal of level H. The signal of level H produced by origin sensor 120on line 235 is applied with the signal of level H produced by delaycircuit 207 to AND gate 208 which, in turn, satisfies three-input ORgate 223, which produces a signal of level H. The output signal of levelH produced by OR gate 223 is applied to buzzer control circuit 138 whichactivates buzzer 137 warning the operator that needle tip 19 is exposed.In addition, a signal of level H produced by OR gate 223 is applied toOR gate 224, and, after a delay determined by delay circuit 225, line231 also carries a signal level of H thereby breaking fault indicatingbreaker 228 and, through OR gate 226 and line 232, breaking circuitbreaker 111 and opening power switch 110.

(vi) Failsafe Shutdown of Operation Due to an Electromechanical Fault

The fine needle aspiration apparatus of the present invention alsoprovides for failsafe shutdown should an error such as a mechanical jamor an electromechanical failure occur. This is accomplished by providingdelay circuits which time various occurrences under normal operation.Should these occurrences take longer than necessary, possibly indicatinga fault, respective delays will expire initiating an organized and safeshutdown of the device.

Specifically, the operation of main solenoid 70 and detent solenoid 66is monitored by a circuit including delay circuit 211 and AND gate 212.If the Q output of flip-flop 195 on line 243 has a signal level of H,indicating that main solenoid 70 should be energized through AND gates198 and 199 and through main solenoid control circuit 160, and if originsensor 120 remains closed producing a signal of level L on line 235, andif this condition exists for a time determined by delay circuit 211,this indicates that syringe carriage 40 has failed to move from theorigin position, despite a command to do so, and is reflected by asignal level of H at the output of AND gate 212.

Also, if the Q output of flip-flop 195 changes from H to L, and iforigin sensor 120 closes before expiration of the delay of circuit 211,indicating that syringe carriage 40 has not stopped at detent 65, ANDgate 212 will produce a signal of level H.

Similarly, if after a time determined by delay circuit 213, the frontdrive bar sensor 125 is not closed indicating the incomplete forwardmovement of syringe carriage 40, as commanded by a signal of level H onthe Q output of flip-flop 195 on line 243, AND gate 214 will produce asignal of level H.

The forward and rearward motion of plunger support bracket 45 aremonitored by delay circuits 215 and 217 and AND gates 216 and 218.Specifically, if, after a time delay determined by delay circuit 215,front plunger limit sensor 127 is not closed, thereby producing a signalof level L on line 236, despite a command to move the plunger supportbracket forward emitted by AND gate 184 on line 237, AND gate 216 willproduce a signal of level H. Similarly, if after a time determined bydelay circuit 217, rear plunger limit sensor 128 has not closed, therebyproducing a signal of level L on line 244, indicating that plungersupport bracket 45 has not moved completely forward despite a command todo so emitted by AND gate 188, AND gate 218 will produce a signal oflevel H.

OR gate 219 accepts the outputs of each of AND gates 212, 214, 216 and218. Should any of these AND gates produce a signal of level H, OR gate219 will produce a signal level of H. This immediately deactivates thedevice by producing a signal of level H on line 238 through OR gate 220(thereby deactivating detent solenoid 66, main solenoid 70 andcommanding motor 55 to turn counter-clockwise thereby returning plunger5 back into syringe body 4, as described above). In addition, a signalof level H output by OR gate 219 will, through OR gate 224 and delaycircuit 225, activate fault indicating breaker 228 via line 231 and,through OR gate 226, activate breaker 111 through line 232. In addition,if the output of OR gate 219 remains at a signal of level H for a timeperiod determined by delay circuit 221 without origin sensor 120closing, thereby indicating that plunger support bracket 45 has notreturned to the origin position shown in FIG. 1a, AND gate 222 willproduce a signal of level H which, via OR gate 223, will activate buzzer137 through buzzer control circuit 138, thereby notifying the operatorthat needle tip 19 is exposed.

The function of fault indicating breaker 228, once it has been trippedopen by delay circuit 225, is to prevent any use of the apparatus, bydisconnecting the power from battery 92 to electronic control circuit109. Once fault indicating breaker 228 has been tripped, theelectromechanical or jam failure must be found and repaired and faultindicating breaker 228 must manually be reset before the apparatus canbe used again.

As will be appreciated by those skilled in the art, the presentinvention is not limited to control by solid-state logic, and could beimplemented, in whole or in part, with microprocessor control, whereinany number of the control functions are programmed via software orhardware. Moreover, as will be appreciated, one or more of the automatedfunctions of the apparatus could be eliminated and performed manually bythe operator.

Furthermore, although the above-described embodiment as set forth hereinis electrically operated, it may be desirable to substitute certainpneumatic components for the electro-mechanical components describedherein. In this regard, the main solenoid 70 could be substituted with apneumatic piston with appropriate valving and a pneumatic gas source,e.g., carbon dioxide.

In lieu of the manual method above described for expressing thecollected sample onto the microscope slide (i.e., detaching the needleand attaching an air-filled syringe to express the sample), the firstembodiment of the invention can be modified to include an automaticfeature, as discussed below. In the modified first embodimentincorporating an automatic expression feature, an orifice is provided inthe rear portion of cylindrical syringe body 4. Additionally, rearplunger limit sensor 128 is relocated so as to be activated before theplunger 5 has been fully extended rearward into contact with the endplate 59. A further sensor (the plunger expression sensor) is alsoprovided to sense the rearwardmost excursion of the plunger 5, i.e.,that position where the plunger contacts the end plate 59. Sensor 128 islocated such that when the plunger support bracket activates the sensor,the orifice in the syringe body does not communicate with the syringechamber 34. However, when the plunger moves to its rearwardmostexcursion and contacts the plunger expression sensor, the orificecommunicates the chamber 34 of the syringe with the atmosphere.

Operation of the apparatus during the aspiration cycle is in allrespects similar to the operation described above, except that, duringthe aspiration cycle, the plunger is only withdrawn until contact ismade with relocated sensor 128. That is, the plunger does not withdrawinto contact with end plate 59. However, after completion of theaspiration cycle, a further automatic sample expression cycle isinitiated with the modified embodiment of the present invention.

The automatic expression cycle operates as follows. After the operatorhas removed the needle and sheath from the patient, and positioned theneedle-tip above a slide upon which the sample is to be expressed, asample expression switch located away from the trigger is activated bythe operator. Upon activation of the sample expression switch, theplunger 5 is withdrawn once again, but in this cycle, the plungercontinues to withdraw until it contacts the plunger expression sensor atend plate 59. This rearward movement of the plunger opens the orifice inthe side of the syringe body to the syringe chamber 34, thus allowingair to fill the barrel of the syringe. After the syringe is filled withair, the motor winds the plunger in slowly, once again blocking theorifice in the side of the syringe, thus trapping air in the syringechamber. The collected sample is then expressed onto the microscopeslide as the motor continues to slowly move the plunger forward. Releaseof the trigger at any time during the expression cycle causes the motorto stop. Depression of the trigger again allows the motor to once againadvance, causing further sample to be expressed. After the plunger is inits forwardmost position, the motor shuts down and the expression cycleis completed.

Additional modifications to the expression cycle can be made to furtherfacilitate automatic sample expression. The expression cycle can bemodified such that the motor moves slowly only during a first phase ofthe forward movement of the plunger, and thereafter speeds up to quicklyreturn the plunger to its forwardmost position. In this manner, thecomplete duration of the expression cycle is reduced such that the motoronly moves slowly while the sample is actually being expressed from theneedle to the slide.

Thus, with minor modifications in the control circuit and sensors of thepresent invention and in the syringe design, an automatic expressionfeature can be incorporated in the first embodiment.

As noted in the above discussion of the first preferred embodiment, atthe completion of each fine needle aspiration procedure, the needle 2,stylet 3, syringe 4 and plunger 5 must be replaced. However, the firstembodiment can be modified to employ a reusable syringe and plunger.When a reusable syringe and plunger are employed, it is no longernecessary to allow operator access to a substantial portion of the upperpart of the apparatus. Accordingly, the apparatus can be substantiallysealed from outside contamination with access being provided only to theextent necessary to replace the needle and stylet. Secondly, byproviding a reuseable syringe and plunger, the operational costsassociated with the use of the apparatus can be reduced since it isnecessary to replace only the needle and stylet after each procedure.However, the provision of a reuseable syringe and plunger is somewhatproblematic since the stylet must be operatively connected to theplunger in the first embodiment.

The aforementioned difficulties can be obviated through the use of anautomatic stylet grabber assembly, discussed hereinafter with referenceto FIGS. 19a, 19b, 20a and 20b.

FIGS. 19a-19b illustrate a first preferred stylet grabber which iselectrically actuated. The grabber includes a pair of grabber pawls 308,309 which are respectively pivotably mounted on a pair of bearing pins312, 313. The forward end of the grabber pawls 308, 309 include grabberjaws 310, 311. A compression spring 315 is located between the pivotpoints defined by the bearing pins 312, 313 and the grabber jaws 310,311 so as to bias the grabber jaws apart as shown in FIG. 19b. Thestylet grabber also includes a cam 318 defined at the end of a solenoidplunger 305 of a solenoid 320. A tension spring 322 biases the plunger305 away from the grabber pawls 308, 309. As shown in FIGS. 19a and 19b,the stylet grabber is located in a central portion of plunger head 307.As in the previous embodiments, the plunger head includes plunger seals306 which maintain airtight contact between the outer periphery of theplunger head 307 and the inner periphery of the syringe body 304.

As shown in FIG. 19a, when the solenoid 320 is energized the solenoidplunger 305 is driven forward against the bias of tension spring 322.Forward movement of plunger 305 causes cam 318 to engage pawls 308, 309,thereby forcing the pawls to pivot about the bearing pins 312, 313 so asto compress spring 315 and close the jaws 310, 311 around the head ofstylet 303.

However, as shown in FIG. 19b, when the solenoid 320 is deenergized, thesolenoid plunger 305 is retracted by the tension spring 322, allowingthe grabber pawls 308, 309 to open under the force of compression spring315.

Those skilled in the art will recognize that the electrically actuatedstylet grabber disclosed herein is easily adaptable for use in theautomatic fine needle aspiration embodiment discussed above bysubstituting the modified plunger shown in FIGS. 19a and 19b for theconventional plunger 5 employed in the previously described embodiment.A conventional syringe can be, but need not be, employed. Any syringeand plunger which cooperate to create the requisite suction uponwithdrawal of the plunger are sufficient for operation of the apparatus.Moreover, casing 1 should be modified such that cover 82 only providesaccess to the front portion of the apparatus. The rear portion of thecasing is sealed to avoid contamination.

The needle and stylet should preferably include a filter 22 extendingbetween the interior surface of the needle and the exterior periphery ofthe stylet as discussed above in connection with FIG. 12 to preventcontamination of the interior of the syringe and plunger. The filtershould be located proximate the rear end of the needle (near theluer-lock connection) to minimize any reduction in volume of the cellsample storage portion of the needle caused by the the filter.

Having thus described the structure of the electrically actuated styletgrabber as well as the applicability of the stylet grabber to the fineneedle aspiration apparatus described above, description will now bemade of the operation of a fine needle aspiration apparatusincorporating an electrically actuated stylet grabber of the typediscussed above.

First, the operator opens the cover of the aspiration apparatus, thusturning the cover switch off and disconnecting power to the device, asdiscussed above. Because the syringe and plunger need not be replaced,it is necessary only to expose the front portion of the syringe(including the luer-lock socket 330) when the cover is opened. Theremainder of the syringe and plunger are sealed against contamination.

The operator thereafter attaches a needle to the syringe body via theluer-lock connections. The needle and stylet are configured such thatwhen the needle is attached to the syringe via the luer-lock, the styletextends into the syringe past the grabber jaws 310, 311 as shown in FIG.19b.

After the needle is attached to the syringe via the luer-lock (and thestylet is positioned inside the grabber jaws), the cover is closed. Aneedle sheath is thereafter attached to the outer portion of theapparatus via a second luer-lock connection in the manner describedabove.

The operator then positions the tips of the needle and stylet asdiscussed above and depresses the safety switch. Activation of thesafety switch energizes the solenoid 320 of the stylet grabber causingthe solenoid plunger 305 to move forward from the position shown in FIG.19b to the position shown in FIG. 19a. As shown in FIG. 19a, movement ofthe solenoid plunger 305 forward forces the grabber pawls 308, 309 topivot about the bearings pins 312, 313 such that the grabber jaws 310,311 are closed around the head of the stylet 303 against the bias of thecompression spring 315. Thus, so long as the solenoid 320 is energized,the grabber jaws 310, 311 securely hold the end of stylet 303.

After turning on the safety switch, the trigger is pulled and theaspiration procedure proceeds as described above.

After the red warning LED 134 signals completion of the procedure, thepower to solenoid 320 is removed, such that solenoid 320 is deenergizedand the solenoid plunger 305 returns to the retracted position thusallowing compression spring 315 to bias the grabber jaws 310, 311 to theopen position illustrated in FIG. 19b.

The sheath is then disengaged from the outside of the housing, the coveris opened and the needle is disengaged form the syringe and withdrawnalong with the stylet. The stylet is then removed from the needle anddiscarded. A fresh air-filled syringe is then connected to the needleand the sample is expressed onto a slide for analysis as describedabove. Alternatively, if the automatic expression feature isincorporated in the apparatus, the sample is automatically expressed asdescribed above, before the needle is removed.

Although the stylet grabber described above is electrically actuated, amanual stylet grabber can also be implemented. In particular, manualmeans can be incorporated within the apparatus to engage jaws 308, 309with the head of the stylet. Moreover, any conventional jaw or chuckcould be incorporated for this purpose. Preferably, appropriate sensorspreclude operation of the apparatus if the jaws are not first properlyengaged with the stylet.

FIGS. 20a and 20b illustrate an automatic mechanical stylet grabberassembly. The mechanical stylet grabber is similar in many respects tothe electrically actuated stylet grabber described above. In particular,like the electrical stylet grabber, the mechanical stylet grabber isadapted to be arranged within the plunger head and for use with a needleof the type described above. Further, the grabber itself includes a pairof grabber pawls 308, 309, a pair of bearing pins 312, 313, acompression spring 315, and a pair of grabber jaws 310, 311 which aresimilar to those of the electrically actuated stylet grabber.

However, unlike the electrically actuated grabber embodiment, thegrabber pawls of the mechanical stylet grabber are specially shaped toinclude curved camming projections 348, 349. Additionally, the plunger 5is modified to include a central cam rod 350 which has an enlarged camhead 352 adapted for engagement with the ends of the camming projections348, 349.

In an apparatus incorporating the mechanical stylet grabber, it is thecam rod of the plunger 350 which is connected to the plunger supportbracket 45 in FIG. 13 for retracting the plunger relative to thesyringe. Thus, at the point during the cycle when the plunger isnormally withdrawn from the syringe in the first embodiment, the cam rodis withdrawn from the position shown in FIG. 20b to the position shownin FIG. 20a in the modified first embodiment such that the enlargedcamming head 352 of the cam rod 350 engages the projections 348 and 349so as to pivot the grabber pawls 308, 309 against the bias of thecompression spring 315 causing grabber jaws 310, 311 to close about thehead of the stylet 303. As the cam rod is further withdrawn, a portionof the enlarged cam head is received within a recess 354 in the plungersuch that the continued retraction of the cam rod 350 causes the entireplunger 5 to retract, as required for the aspiration procedure.

While the mechanical stylet grabber described above includes acompression spring 315 to normally bias the grabber pawls 308, 309 intothe open position, in FIG. 20b the opening of the pawls could beaccomplished without a compression spring by configuring the enlargedcamming head 352 and the grabber pawls 308, 309 such that when theenlarged camming head is in the extended position shown in FIG. 20b, theenlarged camming head cams the grabber pawls 308, 309 into the openposition without the aid of a compression spring.

Those skilled in the art will appreciate that like the electricallyactuated stylet grabber, the mechanical stylet grabber described aboveis adapted for use in fine needle aspiration apparatus of the typepreviously described herein with only minor modifications in thesyringe, plunger, needle, stylet and casing.

Having thus described the mechanical stylet grabber and itsapplicability to fine needle aspiration apparatus of the type describedabove, a description will be made herein of the operation of a fineneedle aspiration apparatus which includes the mechanical stylet grabberdiscussed above.

As with the electrically actuated stylet grabber, the operator begins byopening the cover thereby turning off the cover switch and disconnectingall power to the apparatus. The operator then inserts the stylet intothe syringe while attaching the needle to the syringe via the luer-lock.The operator then closes the cover such that the cover switch isactuated and attaches the sheath to the apparatus housing via a secondluer-lock.

After manually positioning the tips of the needle and stylet, theoperator turns on the safety switch and pulls the trigger thusinitiating the aspiration cycle. The cycle is carried out as describedabove except that central cam rod 350 (and not plunger 5) is connectedto and directly retracted by the plunger support bracket 45. Withdrawalof central cam rod 350 causes the plunger to be withdrawn from thesyringe while also causing the stylet grabber to grab the head of thestylet 303 as shown in FIG. 20a. After the procedure is performed, theplunger is returned to its forward position and the cam rod 350 is movedto its full forward position, causing the grabber jaws 310, 311 toreturn to the open position shown in FIG. 20b.

Upon completion of the procedure, the operator disengages the sheathfrom the housing and opens the cover. The needle and stylet are thendisengaged from the syringe and the stylet is removed from the needleand discarded. The sample is then expressed manually as described above.Alternatively, if the above-described automatic expression feature isincluded in the apparatus, the automatic expression cycle is performedbefore the needle and sheath are removed.

In certain applications it is desirable to conduct a test run of theautomatic fine needle aspiration apparatus before conducting an actualbiopsy on the patient. Additionally, in certain cytological analyses itis preferred to draw the cytological sample into a saline suspension tofacilitate expression of the collected sample.

With reference to FIGS. 13-16, it is apparent that certain problemscould be encountered in attempting to conduct a test run when the needleis not embedded within a target area. Specifically, if the aspirationcycle is so performed, rather than creating a partial vacuum uponwithdrawal of the plunger 5 from the syringe 4, air is drawn into thesyringe air chamber 34 as the plunger is withdrawn. Upon conclusion ofthe test cycle, such air is trapped in the syringe air chamber 34 whenthe stylet tip 26 seals the narrow diameter portion 16 of needle 2. Thistrapped air could have a tendency to stall or place an undue burden uponplunger carriage motor 55, possibly preventing the return of the plungerto its origin position.

Accordingly, to avoid drawing air into the syringe chamber 34 during atest run, or to otherwise introduce saline into the cell sample storageportion 20 of the needle 2, the sheath 6 can be modified to accommodatea test reservoir apparatus as illustrated in FIG. 21. The sheath 6,stylet 3, needle 2 and sheath finger guide 13 are identical to theembodiment of FIGS. 2-8 except that sheath 6 is modified to defineexternal threads 350 to removably receive internal threads 351 of hub352 or some other appropriate attachment means of a test reservoirapparatus 340.

A reservoir support housing 357 is threaded via threads 355, 356 to hub352 and defines an interior chamber 359. A pouch 360 is located withinchamber 359 and has flanged end 362 captured between shoulders definedby hub 352 and reservoir support housing 357. Pouch 360 is made from asoft, puncturable, resilient material, such as silicone or surgicalrubber and is filled with a small volume of air, saline, or acombination thereof 361. Chamber 359 and pouch 360 are dimensioned suchthat a small space remains between the interior wall of chamber 359 andthe outer surface of the pouch. Vent holes 358 are defined along thewall of chamber 359.

Having described the structure of the test reservoir apparatus, itsoperation is hereinafter described. Should the operator determine that atest run of the apparatus should be performed or that saline should bedrawn into the cell sample storage portion of the needle beforeperforming a biopsy on the patient, a modified sheath having a testreservoir apparatus 340 threaded thereto should be selected.

To initiate the test run, the operator installs the modified syringe andsheath in accordance with the procedure described above with respect tothe first preferred embodiment of the invention, including installingthe syringe 4, closing the cover 82 and mounting the sheath 6 vialuer-lock connections 11, 81.

The operator thereafter initiates a test run by performing thesafety/trigger sequence discussed above. Depression of the triggercauses needle 2 to advance forward, piercing pouch 360 and aspiratingthe contents 361 of the pouch (i.e., the saline, air or mixturethereof). The pouch is air tight, so that the amount of air or fluiddrawn into the syringe is limited to the volume of the pouch. Becausethe pouch has a small volume (e.g., 25-50 λ), an insufficient amount ofgas or fluid is drawn into the syringe to have any adverse affect uponmotor performance or upon return of the plunger to its origin position.

Upon completion of the test aspiration cycle, most of the contents ofpouch 360 remain within the cell sample collection portion 20 of theneedle 2. Accordingly, if it is desired to suspend the biopsy sample insaline, pouch 360 should be filled with saline for the test run. Aftercompletion of the test run, the test reservoir apparatus 340 isunthreaded from sheath 6 at threads 350, 351, discarded, and theapparatus is tested and ready for biopsy on the patient.

As will be apparent to those ordinarily skilled in the art, the test runapparatus of FIG. 21 thus performs a dual function of enabling a testrun and introducing saline to the cell sample storage portion of theneedle.

Although the description thus far has been directed to an automaticapparatus for performing fine needle aspiration, it will be appreciatedby those skilled in the art that one or more of the operations of theautomatic apparatus can be performed manually, thus simplifying andreducing the cost of the overall apparatus.

To this end, FIGS. 22-23 illustrate a second embodiment, which ismanually operable, but which provides many of the beneficial features ofthe present invention. The manual embodiment of FIG. 22 includes avariable gage needle 402, configured as in FIGS. 2-8 or 9. A sheath 406surrounds the needle in the manner described above with respect to theautomatic embodiment, and can also be one of various configurations, asdescribed with reference to FIGS. 2-8, 10 and 11. In lieu of the sheathluer-lock connection 11 in FIG. 13, sheath 406 in the first manualembodiment has an outwardly tapering mouth 411 to facilitate insertionof the needle assembly therein. Stylet 403 is located within needle 402and, when in its forwardmost position, occludes the narrow diameterportion of needle 402 (not shown in FIG. 22). Needle 402 is connected tosyringe body 404 via luer-lock connections 418, 431 on the needle andsyringe body, respectively. Syringe plunger 405 is located withinsyringe body 404 and defines, with the syringe body, a syringe airchamber 434. Stylet 403 extends through plunger 405 and is movabletherewith. Stylet 403 has stylet head 427 which is press fit into theend of plunger 405, or otherwise removably retained therein in anyexpedient manner.

Stop 423 is slidable along needle 402, and is securable to the needlevia thumbscrew 422 or in some other expedient manner. A gage 424 isprinted or inscribed on needle 402, and may include color-coded segmentsto facilitate operator-observation of the extent of penetration and thereciprocation excursion range, in a manner hereinafter described in moredetail.

Syringe handle portion 426 is integral with or connected to syringe body404. Plunger handle portion 428 is integral with or connected to plunger405, and is slidable along rails 430 of the syringe handle portion inthe axial direction. Holes 429 and 432 are provided in syringe handleportion 426 and plunger handle portion 428, respectively, to permitinsertion and withdrawal of the stylet.

The entire unit illustrated in FIG. 22 may be configured as a sterilizeddisposal unit, in which case, the syringe handle portion and plungerhandle portions are made from a low-cost, light-weight plastic.Alternatively, the handle portions can be reusable, made from, e.g.,stainless steel, and the syringe, plunger, needle, stylet and sheath canbe disposable and removably insertable into the handle portions.

Rails 430 of syringe handle portion 426 can be configured with helicalspring means (similar to springs 61 in FIG. 16), to bias the handleportions to the position illustrated in FIG. 22.

FIG. 23 illustrates a modification of the embodiment disclosed in FIG.22, which includes a cell expression valve, indicated generally as 520.In the FIG. 23 embodiment, needle 502 is substantially the same asneedle 402, except that it includes orifice 509 and valve hub 507 at itsend remote from the needle tip. Valve hub 507 locates rotary gate valve510. Rotary gate valve 510 has orifice 508 adapted to communicate withorifice 509 of the needle when in the open position illustrated in FIG.23. The needle, with the valve assembly, is connected to the syringeassembly as in FIG. 22, via luer-lock connections 518, 531. Gate valve510 is rotatable about needle 502 between valve hub 507 and luer-lockconnection 518 to block orifice 509 when in its closed position.

Having described the structural aspects of the embodiments of FIGS.22-23, the operation thereof is hereinafter described with reference tothe figures.

Similar to the discussion above with respect to dials 71, 72 inconnection with FIG. 13, the operator first determines the desired depthof penetration and range of excursion based upon the size and locationof the target area being biopsied. After the maximum penetration depthhas been determined, the operator sets the excursion stop 423 viathumbscrew 422, thereby limiting the forwardmost movement of the needlewith respect to the sheath. The operator also determines the appropriatecolor-coded or otherwise designated portion of the gage 424corresponding to the desired reciprocation limit. Having undertakenthese preliminary set-up steps, the operator is now ready to commencethe biopsy procedure.

First, the sheath and related assembly are positioned next to the targetarea in the manner described above with respect to the first embodiment.The operator should carefully observe gage 424 while inserting sheath406 to ensure that the needle does not emerge from the sheath while thesheath is being positioned. If an ultrasonic transducer is being used,the operator probes until the target area and needle entry point aredetermined. If the target area is the prostate and ultrasound is notutilized, the apparatus is inserted trans-rectally and the operatorpalpates the prostate to determine the target area and needle entrypoint.

Thereafter, the operator pushes the needle forward by pushing forward onthe handle assembly, causing the needle to protrude from the sheath 406and pierce the target area. Forward movement of the needle is limited bythe abutment of stop 423 with end 411 of sheath 406.

The operator then squeezes together the plunger handle portion 428 andsyringe handle portion 426, thereby causing withdrawal of the stylet.Such withdrawal unoccludes the narrow diameter portion of the needle andcreates a vacuum at the needle tip. The full excursion of the plungerhandle portion 428 is determined to correspond to the extent of thedesired plunger and stylet withdrawal. If the handle portions arereusable, variable limits (e.g., movable stops or pins in the syringehandle portion 426 which engage the plunger handle portion 428) can beincorporated in the handle portion to render the plunger excursionvariable. When the handle portions are fully squeezed together, the tipof the stylet is in the large diameter portion of the needle, asdiscussed above. If the optional springs are incorporated in the handleportions, as discussed above, continuous pressure is required tomaintain plunger withdrawal and keep the stylet from occluding theneedle. Accordingly, should the operator be required to immediatelywithdraw the needle, e.g., if the patient begins to move, the operatorneed only release the plunger handle portion so that it will return toits initial position, causing the stylet to move forward, occluding thenarrow portion of the needle. This return of the plunger and styletensures that the stylet is returned to its initial position to avoidcontamination of the sample, e.g., with rectal mucosa or bacteria, uponwithdrawal of the needle.

After the plunger has been withdrawn, the procedure is continued byreciprocating the handle assembly so that the needle reciprocates withrespect to the sheath. Forward reciprocation is limited by theengagement of stop 423 with sheath end 411. The operator controls returnreciprocation precisely and conveniently by observing the color-coded orotherwise indicated gage 424, thereby ensuring that the needle is notwithdrawn too far, e.g., back into the sheath.

As discussed above, reciprocation of the assembly causes cytologicalsample to be collected in the sample storage portion of the needle.After sufficient sample is collected, the operator squeezes the syringeand plunger handle portions together to the closed position or, if theoptional springs are included on handle rods 430, simply releases theplunger handle portion. Forward movement of the plunger and styletreleases the vacuum and causes the stylet to occlude the needle,protecting the sample from contamination during withdrawal, as discussedabove.

The operator then expresses the sample onto a microscope slide in one ofseveral methods, depending on the particular embodiment of the devicewhich is employed.

In the embodiment disclosed in FIG. 22, the stylet 403 can be removed bygrasping stylet end 427 and pulling it through holes 429, 432. Theneedle hub is then disconnected from the syringe luer-lock 431.Thereafter the handle portions are pulled together causing the syringeair chamber 434 to fill with air. The luer-lock connection is thenreestablished and the operator depresses the plunger with the needle tipadjacent to a microscope slide. Depressing the plunger causes the sampleto be expressed from the sample storage portion to the slide. Althoughnot discussed above in connection with FIG. 13, it will be appreciatedby those skilled in the art that this method of sample expression canalso be utilized in connection with the automatic embodiment of FIG. 13,discussed above. Also, in lieu of removal of the stylet, the syringebody can include an orifice for communicating the air chamber with theatmosphere, as discussed in more detail below.

Alternatively, the needle can be disconnected and attached to anair-filled syringe for sample expression, as discussed in connectionwith the first embodiment.

In the embodiment illustrated in FIG. 23, expression of the sample isfacilitated by the provision of valve 520. To express the sample in thisembodiment, the operator opens valve 520 by rotating gate 510 untilorifices 508 and 509 are in communication. The operator then withdrawsthe plunger as described above, drawing air into the syringe airchamber. The operator then closes valve 520, blocking communication ofthe orifices and removes the stylet. The sample is now ready forexpression in the manner described above. Although not incorporated inFIG. 13, it will be appreciated that the FIG. 13 embodiment could bemodified to incorporate a valve identical to valve 520 to facilitatesample expression in the FIG. 13 embodiment.

Many of the advantages associated with the automatic embodiment areachievable with the present manual embodiment. First, the biopsy can beperformed by a single operator without requiring cumbersomemanipulations. Moreover, a stylet is used to occlude the needle bothduring insertion and withdrawal of the needle, thus avoiding thecontamination of the target area and the sample. Furthermore, stop 423and gauge 424 provide simple means for standardizing the procedure andmonitoring the needle excursion. Finally, all contaminatable portions ofthe apparatus are disposable and are inexpensive to manufacture.

A third embodiment of the present invention, which is manually operable,is illustrated in FIGS. 24a-24c.

FIGS. 24a-24c illustrate a further needle and sheath assembly forcollecting biopsy samples from an internal organ for cytologicalanalysis in accordance with the fine needle aspiration technique. Theapparatus is adapted to retrieve a cytological sample of sufficientvolume (e.g., approximately 25-50 λ of cells and intracellular fluidfrom tissue) without retrieving a core. Moreover, the apparatusfacilitates retrieval of the sample only from the target area, withoutcollecting undesired debris or contaminants. With this apparatus,biopsies can be performed by a single person, and standardization of thefine needle aspiration technique is achievable.

The embodiment illustrated in FIGS. 24a-24c consists of a needle 610(e.g., 21-24 gauge) with a closed or bullet tip 611 and a series of sideports 612 positioned just behind the tip opening. To facilitate sampleexpression, the side ports should be located substantially in the sameradial direction or only slightly offset. This will ensure that thesample, when expressed, can be directed onto a microscope slide. Asleeve 620 (e.g., 22-19 gauge) is closely fitted around needle 610 suchthat a seal of the side ports 612 is effected when the sleeve 620 is inits forwardmost position (as illustrated in FIGS. 24a and 24b). Inaddition, to improve the seal between needle 610 and sleeve 620 and toreduce the required manufacturing precision, one or both of the needleand sleeve can be coated with plastic or silicone or other suitablematerial, to act as a gasket or seal between the needle and sleeve. Therear end of the sleeve 620 has annular ring 621 and outer retaining tube622 secured thereto. The outer retaining tube locates an inner retainingtube 631 permanently fixed to a needle hub 630 fixed to needle 610. Acompression spring 626 surrounds the needle 610 and is interposedbetween annular ring 621 and needle hub 630. Spring 626 is surrounded byouter retaining tube 622 and inner retaining tube 631.

A sheath 640 surrounds sleeve 620 and outer retaining tube 622 and isprovided at its end adjacent to the needle tip with a tip or handlingapparatus 641 appropriate for the particular region of the body beingbiopsied. The exemplary tip 641 in FIG. 24 is effective, e.g., forbiopsy of any soft organ to which access can be gained through the skin,e.g., the breast.

The hub 630 of the needle can be provided with a valve 635 which has aport 636 which is alignable with a port 613 in the needle. Alignment ofthe needle and valve ports opens the valve, allowing air to be drawninto the syringe 650. The needle hub 630 is provided with a luer-lockconnection 632 which mates with a syringe luer-lock connection 651. Aconventional syringe can be used and fitted to the needle and sheatharrangement, for use with conventional fine needle aspiration handlemechanisms or, for example, a handle as illustrated in FIG. 22.Alternatively, the syringe, needle, sleeve, sheath and handle can beintegrally configured as a disposable unit.

A filter 653 is provided in hub 630, and performs the functionsdiscussed above in connection with FIG. 12.

Turning to the operation of the above-described apparatus, the initialposition of the apparatus is illustrated in FIG. 24a, with the sleeve620 and needle tip 611 in the fully retracted position within sheath tip641. The operator thereafter pushes the syringe forward with respect tothe sheath, causing the needle 610 and sleeve 620 to move outward fromthe sheath as a unit and penetrate the target area of the tissue to besampled as illustrated in FIG. 24b. As is apparent from FIG. 24b, theports 612 of needle 610 are occluded by the sleeve 620 while the needlepenetrates the tissue into the target region. During this penetrationstage, the needle and sleeve are moved forward until annular ring 621 ofthe sleeve 620 abuts a shoulder of the sheath 640 as illustrated in FIG.24b. Spring 626 has a spring constant sufficient to enable the needle610 and sleeve 620 to move forward as a unit and abut the shoulder ofthe sheath without resultant relative movement between the inner andouter retaining tubes 631, 622.

The operator thereafter pushes the syringe forward further, causingcompression of spring 626 which results in a relative movement betweenouter retaining tube 622 and inner retaining tube 631. As a consequence,needle 610 moves forward with respect to sleeve 620 exposing ports 612.The syringe can be evacuated by withdrawing the plunger (not shown)either before or after the step illustrated in FIG. 24c. After creatinga vacuum in the syringe, the needle is reciprocated while unoccluded asillustrated in FIG. 24c for a predetermined number of cycles empericallydetermined by the desired sample yield. Thereafter, the needle andsheath assembly is withdrawn, thereby returning it to the positionillustrated in FIG. 24a. The vacuum can be released at any convenienttime before or after the needle has been withdrawn.

Once withdrawn, and after the vacuum has been released, valve 635,similar to valve 520 in FIG. 23, can be opened and air can thereafter bedrawn into the syringe. Alternatively, the valve 635 can be opened torelease the vacuum. The valve 635 is then closed, and the cell sample isexpressed onto a microscope slide by holding the sheath, pushing theneedle out so that the ports are exposed and pushing the syringe plungerclosed, or allowing it to close if springs are embodied in the syringehandle.

In lieu of the above-discussed methods of expression, the embodiments ofFIGS. 22 and 24a-24c can be modified to incorporate alternativeexpression apparatus. In particular, the syringe bodies of each of theseembodiments can be modified to include an orifice at the rearward end ofthe cylindrical syringe body. Additionally, the handle mechanisms ineach of these embodiments can be modified to facilitate two plungerwithdrawal limits, i.e., a sample collection limit and a sampleexpression limit. Any suitable stop for the handle can be utilized toestablish the limits, including an adjustable stop mechanism or aremovable pin, to vary the rearwardmost movement of the plunger handleportion with respect to the syringe handle portion. During the samplecollection cycle, the plunger is withdrawn to the sample collectionstop, in which position the orifice in the syringe body does notcommunicate with the syringe chamber. However, during the sampleexpression cycle, the plunger handle portion is withdrawn beyond thesample collection limit to the sample expression limit, thus allowingair communication through the orifice in the syringe body to the syringechamber. The plunger is then returned to the forwardmost position,thereby compressing the air and expressing the sample through the needletip onto a microscope slide for further analysis. The outer sleeve mustbe retracted during expression by this method with the third embodiment(FIGS. 24a-24c).

Although the third embodiment has been disclosed in terms of manualoperation, it will be appreciated that the apparatus is easily adaptedto automation of one or more of the steps of the process, includingreciprocation, needle advancement, needle withdrawal and cellexpression.

FIG. 25 illustrates a fourth embodiment of the invention whichillustrates modifications to the first (FIG. 13) embodiment to adapt itfor use with a needle and sheath assembly as disclosed in FIG. 24a-24c.FIG. 25 depicts the left-hand portion of FIG. 13, noting modificationsthereto. In FIG. 25, similar components to FIGS. 24a-24c are designatedby the reference numerals in FIGS. 24a-24c, increased by 100.Specifically, the FIG. 25 assembly includes a needle 710, sleeve 720,needle hub 730, filter 753, luer-lock connections 732, 751, syringe 750,outer retaining tube 722, inner retaining tube 731, compression spring726, annular ring 721 and sheath 740. Retaining tube 722 is heldslidably within an extension of sheath 740 by ring gasket 754, which canbe rubber or silicone or any other material having suitable properties.

The apparatus disclosed in FIG. 25 is automatically controlled by thecontrol circuit of FIG. 18 to operate identically with the embodiment ofFIGS. 24a-24c. The control of the fourth (FIG. 25) embodiment issubstantially identical to the control of the first embodiment, as setforth in FIGS. 17-18.

In operation, the operator inserts the syringe and needle assembly,closes the cover and connects the sheath, as discussed in connectionwith the FIG. 13 embodiment. To initiate the aspiration cycle, theoperator depresses the safety and trigger in the sequence discussedabove. In the first step of the automatic aspiration cycle, the carriageassembly moves forward (carrying with it the syringe and needleassembly) until the forwardmost excursion of the needle has been reached(i.e., that excursion corresponding to the position illustrated in FIG.24c and corresponding to position "B" in FIG. 1). Forward excursion ofthe carriage assembly is limited by contact of the drive bar with stop69. The initial forward excursion causes the needle to penetrate thetarget area in the manner discussed above with reference to the firstembodiment. Thereafter the carriage assembly moves rearward under thebias of springs 61 until it abuts detent 65 which is actuated asdiscussed above by detent solenoid 66. The fourth embodiment isconfigured such that the needle 710 and outer sleeve 720 remain in theposition illustrated in FIG. 24c when the carriage contacts detent 65(corresponding to position "C" in FIG. 1). Vacuum is then created in thesyringe chamber by withdrawing the plunger in the manner described abovewith reference to the first embodiment. Thereafter, under the directionof the control circuit, the carriage assembly reciprocates apredetermined number of times while the needle is open as depicted inFIG. 24c (i.e., between positions corresponding to "B" and "C" in FIG.1). After the control circuit senses the completion of the predeterminednumber of reciprocations, the motor is energized counter-clockwisecausing the plunger to retract, thus releasing the vacuum. Detentsolenoid 66 is thereafter de-energized, allowing detent 65 to withdrawand the carriage assembly to once again return to its origin position.

As will be appreciated from the foregoing, the construction of theneedle and outer sleeve assembly ensures that the needle tip is occludedduring the penetration and withdrawal stages of the aspiration cycle.Furthermore, the reciprocation of the needle in the aspiration cycleoccurs with the needle unoccluded, causing sample to be drawn into thesample collection chamber. As is apparent from the foregoing, themovements which the fourth (FIG. 25) embodiment undergoes are identicalto those of the first (FIG. 13) embodiment, thus enabling identical orsubstantially identical control circuitry to be implemented in the firstand fourth embodiments.

As with the first embodiment, an automated cell expression cycle canalso be added to the fourth embodiment. Specifically, as in the firstembodiment, an orifice can be located in the rear end of the cylindricalsyringe body, sensor 128 of FIG. 13 can be relocated, and an additionalplunger expression sensor can be added. With these modifications, theautomatic sample expression cycle operates as follows.

During the aspiration cycle, the plunger is not withdrawn to end plate59 in FIG. 13, but is instead moved only to a first limit positioncorresponding to the relocated plunger rear limit sensor 128. In thisfirst position, the orifice in the syringe body does not communicatewith the syringe chamber 34.

However, during the automatic sample expression cycle, the plunger isfurther withdrawn until the plunger expression sensor is actuated, inwhich position the orifice communicates with the syringe chamberallowing the chamber to fill with air. As with the automatic expressioncycle discussed above with reference to the first embodiment, theplunger is then moved forward slowly, blocking the orifice, which thencreates pressure in the syringe chamber 34 and causes the sample to beexpressed from the needle onto the slide. As will be appreciated withreference to FIG. 24c, the main solenoid must be actuated during theautomatic sample expression cycle to open the needle ports (i.e., towithdraw the sleeve 720 with respect to the needle 710). The expressioncycle is designed so that the sample will continue to be expressed solong as the operator maintains pressure on the trigger. The controlcircuit for the automatic expression feature can be configured such thatafter the trigger has been released, again depressing the trigger causesthe sample to continue to be expressed. Additionally, the controlcircuit can be configured such that after a predetermined time ormovement of the plunger, the motor speeds up to quickly return theplunger to its forwardmost (closed) position. The time at which themotor begins to speed up should be determined to correspond to a timewhen all or substantially all of the sample has been expressed from thesyringe.

It will be appreciated that certain modifications to the aspirationcontrol circuit can also be made to facilitate the automatic expressionfeature of the invention. In particular, the above-described aspirationcycle of the FIG. 25 embodiment can be modified such that the plunger isnot returned to the forwardmost or closed position at the end of theaspiration cycle. This modification is possible in the fourth embodimentsince movement of the plunger is not required to occlude the needle atthe time of needle retraction. With the plunger still withdrawn to thefirst limit position at the conclusion of the aspiration cycle, theplunger need only be moved rearward a small distance to open upcommunication between the orifice and the syringe chamber. Thereafter,upon initiating the sample expression cycle, expression proceeds in themanner discussed above.

As will be appreciated by those ordinarily skilled in the art, thefourth embodiment of FIG. 25 allows for the use of a permanent(non-disposable) syringe and plunger mounted in a sealed portion of thegun. To this end, access through the cover can be limited to only theluer-lock connection of the syringe if a permanent syringe and plungerare used.

Furthermore, although the carriage and the detent 65 are described ascontrolled by main solenoid 70 and detent solenoid 66, either or bothsolenoids could be substituted with other appropriate means, including,but not limited to, D.C. servo or stepping motors with appropriatelinkages providing the desired reciprocatory movements as discussed inrelation to the first embodiment. Also, it may be desirable tosubstitute certain pneumatic components for the electro-mechanicalcomponents described herein. For example, the main solenoid 70 could besubstituted with a pneumatic piston with appropriate valving and apneumatic gas source, e.g., carbon dioxide.

Numerous characteristics and advantages of the invention have been setforth in the foregoing description, together with details of thestructure and function of the invention, and the novel features thereofare pointed out in the appended claims. The disclosure, however, isillustrative only, and changes may be made in detail, especially inmatters of shape, size, and arrangement of parts, within the principleof the invention, to the full extent extended by the broad generalmeaning of the terms in which the appended claims are expressed.

What is claimed is:
 1. An apparatus for aspirating a cytological samplefrom a target area, comprising:a needle having at least one opening;occlusion means for blocking said at least one needle opening when theneedle is inserted into and withdrawn from the target area; a sheathsurrounding at least a portion of said needle and cooperating with saidocclusion means to selectively unblock said at least one needle opening;reciprocation means for reciprocating said needle and said occlusionmeans relative to said sheath, said reciprocation means includingreciprocation control means for controlling the reciprocation excursionof said needle within the target area, said reciprocation control meansincluding penetration control means for limiting the extent ofpenetration of the needle into the target area, said penetration controlmeans including a first stop limiting the advancement of said occlusionmeans exteriorly of said sheath and a second stop limiting theadvancement of said needle, wherein said second stop is positioned topermit extension of said needle outwardly of said occlusion means withsaid occlusion means advanced to said first stop; and vacuum meansconnectable to said needle for selectively creating a partial vacuum atsaid needle opening.
 2. The apparatus for aspirating a cytologicalsample as set forth in claim 1, wherein said needle has only one openinglocated at its tip.
 3. The apparatus for aspirating a cytological sampleas set forth in claim 1, wherein said needle has a closed tip and saidat least one opening is on the periphery of the needle near its tip. 4.The apparatus for aspirating a cytological sample as set forth in claim1, wherein said at least one opening is on the periphery of the needlenear its tip.
 5. The apparatus for aspirating a cytological sample asset forth in claim 4, wherein said at least one opening is chamferred.6. The apparatus for aspirating a cytological sample as set forth inclaim 4, wherein said occlusion means comprises a sleeve surroundingsaid needle which blocks said at least one opening when in its occludingposition.
 7. The apparatus for aspirating a cytological sample as setforth in claim 1, wherein said occlusion means comprises a stylet insidesaid needle which blocks said at least one opening when in its occludingposition.
 8. The apparatus for aspirating a cytological sample as setforth in claim 7, wherein said stylet passes through but does not fullyoccupy said sample collection portion.
 9. The apparatus for aspirating acytological sample as set forth in claim 8, wherein said vacuum means isa syringe and syringe plunger, and said stylet is connected to saidsyringe plunger.
 10. The apparatus for aspirating a cytological sampleas set forth in claim 9, wherein said stylet occludes said at least oneopening when said syringe plunger is in its forwardmost position, andthe syringe plunger is in its forwardmost position when the needle isinserted into and withdrawn from the target area.
 11. The apparatus foraspirating a cytological sample as set forth in claim 9, furthercomprising grabber means for detachably connecting said stylet to saidsyringe plunger.
 12. The apparatus for aspirating a cytological sampleas set forth in claim 1, wherein said reciprocation control meanscomprises forward and rearward stops for limiting movement of theneedle.
 13. The apparatus for aspirating a cytological sample as setforth in claim 1, wherein said reciprocation control means comprises astop for limiting forward movement of the needle and a visual gage formonitoring rearward movement of the needle.
 14. The apparatus foraspirating a cytological sample as set forth in claim 1, furthercomprising electrical control means for automatically controlling theapparatus.
 15. The apparatus for aspirating a cytological sample as setforth in claim 1, further comprising test apparatus means forintroducing a limited volume of at least one of air and saline into thesample collection portion, said test apparatus means being detachablymounted to said sheath.
 16. The apparatus for aspirating a cytologicalsample as set forth in claim 1, wherein said needle, sheath, occlusionmeans and vacuum means are disposable.
 17. The apparatus set forth inclaim 1, further comprising bias means interposed between said needleand said occlusion means.
 18. An apparatus for aspirating a cytologicalsample from a target area, comprising:a needle having a closed tip andat least one peripheral opening; a sheath; an outer sleeve surroundingsaid needle, and cooperating with said sheath, to be movable relative tosaid needle to and from an occluding position in which said at least oneperipheral opening of said needle is blocked by said outer sleeve;reciprocation means for reciprocating said needle and said outer sleevebetween a first position wherein said needle and said outer sleeveextend within said sheath and a second position wherein said needle andsaid outer sleeve extend exteriorly of said sheath, said reciprocationmeans including reciprocation control means for controlling thereciprocation excursion of said needle within the target area saidreciprocation control means being operable to permit reciprocation ofsaid needle in an unoccluded position relative to said outer sleeve withsaid outer sleeve fully extended relative to said sheath; and means forcreating a partial vacuum in said needle.
 19. An apparatus foraspirating a cytological sample from a target area, comprising:a needlehaving a closed tip and at least one peripheral opening; an outer sleevesurrounding said needle, said needle being movable relative to saidouter sleeve to and from an occluding position in which said at leastone peripheral opening of said needle is blocked by said outer sleeve;bias means cooperating with said needle and said outer sleeve forbiasing said at least one peripheral opening towards said occludingposition; means for creating a partial vacuum in said needle; and meansfor moving the needle into and out of the target area while it is in itsoccluding position, and for reciprocating said needle over apredetermined excursion range within said target area while it is awayfrom its occluding position.
 20. The apparatus for aspirating acytological sample as set forth in claim 19, wherein said means forcreating a partial vacuum, and said means for moving and reciprocatingsaid needle are electrically actuated and controlled.
 21. The apparatusfor aspirating a cytological sample as set forth in claim 19, wherein atleast one of said means for creating a partial vacuum, and said meansfor moving and reciprocating said needle are pneumatically actuated andelectrically controlled.
 22. The apparatus for aspirating a cytologicalsample as set forth in claim 19, wherein at least one of said means forcreating a partial vacuum, and said means for moving and reciprocatingsaid needle are manually actuated and controlled.
 23. The apparatus foraspirating a cytological sample as set forth in claim 19, and furthercomprising:means for unoccluding said at least one peripheral opening byrelative movement of said needle and said outer sleeve upon advancementof said needle and said outer sleeve a predetermined fixed distancetowards said target area.
 24. The apparatus set forth in claim 23,wherein said means for unoccluding said at least one peripheral openingincludes a sheath surrounding at least a portion of said needle andcooperating with said outer sleeve.